I feel really uncomfortable around other people

The thing I picked up immediately in what you're asking is how you don't like other people because "they make me nervous and scared." If someone said that to me in a therapy session, I'd want to understand this much more with them, and what this "nervous and scared" experience is all about: perhaps starting with the question, "what's the earliest memory you have of feeling uncomfortable around people." The idea would be to try to understand all of what it means for you to be around people, and the history of the experience, without labeling it wrong or passing judgment on it.

From there what might come is that certain people, and their character traits, might be harder to be around for you because of experiences that you've had with similar situations in your life. Or, it could certainly be something completely different. It would be most important to understand it much more deeply considering the amount of distress it causes you, and in doing so we could begin to see it as "normal for me."

What you're experiencing is anxiety, it's actually quite common. Good news - you're not alone in this experience! That being said, it can be so frustrating and upsetting to have to contend with the anxious thoughts that come up in our heads, sometimes without any warning. Additionally, nighttime is a particularly vulnerable time for a lot of people wherein anxiety rears its' ugly head even more so. We aren't as distracted at night and our resources are more depleted so we can't fight back against these thoughts as effectively as usual. 

It can be helpful to externalize our anxiety, give it a name, like "Judy" or "Bill" for example (or perhaps something more sinister like Lord Garmadon??). The naming is all up to you, what comes to mind for you when you think of your anxiety, now what is a name that's fitting? The act of externalizing separates us from the anxiety a bit and makes it a little more tolerable. If you can think of your anxiety as just something else to handle rather than it being a part of your personality, this is usually helpful. 

Additionally, I recommend not avoiding the situations that make you feel this way. Our brains have to learn what is an actual threat and what is not. Right now, your brain thinks that crowds are a threat, if you can practice some deep breathing and stay in the crowd, you will start to teach (or rewire) your brain, letting it know that the crowd is not dangerous to you. Think of your brain as an overprotective parent. Your brain is overreacting in these situations to try and keep you safe. It just needs to learn that the situation is not a danger to begin with. 

I think you have a lot of insight into what’s going on - being able to pinpoint the issue you’re facing and describe the responses it evokes. It sounds like you may be dealing with social anxiety and it may be beneficial to talk to a professional counselor about this. A therapist can help you develop tools (or coping strategies) for dealing with these situations. From what you’ve shared, you might benefit from animal assisted therapy. Equine therapy is a great approach, or even just working with a therapist who uses animal assisted therapy integrated with a traditional approach to counseling.

Reaching out to talk about these issues is an important first step. Finding professional services might be recommended if these issues are happening more and more. A few things to note...

Anger is an important secondary feeling to be aware of- it keeps us safe, allows us to stand up for ourselves or others....but it also harbors a myriad of disadvantages. But its secondary. It's more necessary to understand the primary emotions behind the anger- worry, confusion, frustration, fear, loneliness, etc...

Anxiety has a lot to do with worrying about the future, especially things that we might not be able to control. If we focus our worry on negative things- mistakes, failures, or messups then we will inherently tell ourselves negative things about ourselves.  People tend to dwell on the negatives without embracing, or as t least recognizing, the positives.

Since you're aware of your sensitivity to being among large groups of people, then continue to satisfy this and stay away from crowds as much as reasonably possible.

It is also fine to prefer the companionship of animals, as long as it is not to the exclusion of relationships with people.

Recognizing this feature about yourself is another example of self-understanding.

The only point to consider is the reason you avoid talking with other people.

If its because of bad or stressful encounters, betrayals or some type of violation, then having this relationship pattern remain in your mind, may introduce new problems such as loneliness from lack of close friends.

What you should do is honestly understand whether you avoid people from fear of being hurt or exploited in some way or because you genuinely prefer solitude.

If you have the right combination of people/solitude/animals, then great!

If not, then consider the confidential office of a therapist for new understanding of yourself and your social interests.

Thanks for sharing your concern!  I think you'd be surprised if you knew how many people feel the same way.  Being in crowds can provoke anxiety (one of the symptoms of anxiety is irritability or anger, like you described).  For some people, that's just because of their personality (if you tend to be more introverted, being around lot of people is really draining).  For others, it can point to a diagnosis of social anxiety.

I'd recommend starting by writing down your self-talk.  It sounds like you are telling yourself a lot of negative messages (as you mentioned, having imaginary conversations and assuming people are judging you).  Write down the thoughts that are leading to you feeling terrible and crying.  Maybe that's:  I'm stupid, Everyone else is having a good time so I should be too, There's something wrong with me.  Just writing these down is an important starting point because it allows you to be objective to your thoughts.  When you see them on paper, you can start to identify the lies and reframe them.  Next to your negative thoughts, write some positives:  I have something to offer, I'm okay the way I am, It's okay to prefer 1:1 relationships, etc.  Hopefully even as you read some of those suggestions, you feel a little lighter and more okay with yourself.  

Take care!

So amazing that you are aware of your social anxiety and distress with others you are in relationships with. You have taken the first step toward a journey of healing! 

Secondly, make an appointment with a therapist who specializes in neurofeedback and biofeedback treatment. A test is needed to determine which areas of your brain are ‘on’ and which areas of your brain are ‘off’. Then it will be focused treatment which will speed your healing.