It sounds like you have taken on a caretaker role for a while as well as experienced some pretty severe interpersonal trauma. It makes sense that you would feel nervous around people. Working through the trauma of an abusive relationship in itself can be a difficult process. And then to add on the caretaker part can make things even more difficult.
First off, you may want to seek support to work through what you have experienced. Many cities offer support with survivors of domestic violence and there is a hotline to help with this 888-724-7240 as well as online resources. Processing the isolation of this relationship as well as working with your son can help to overcome the anxiety related to others. Accessing autism support networks may be of support as well. Other parents that will understand your experiences are a good and tend to be safer place to start in attempting to connect to others.
Very importantly, go slow and be kind to yourself as you begin to adapt to a new life of allowing others to care for you as you so clearly have for others.
First off, there is nothing wrong with you. In fact, having random thoughts we feel we cannot control is actually quite common and normal.
Sometimes our thoughts think they are protecting us (if we think we aren't worth anything, it won't hurt when we get rejected) but they are actually doing quite the opposite. They are keeping us "stuck" and creating a self-prophization. (If I think I am not worth anything, I don't have to try, and I will keep proving to myself that I am not worth anything).
There are many techniques to work through and start to change our negative self-talk. There are actually many self-help workbooks that can help with this as well.
A technique I like to use is meditation or mindfulness. This can teach us to accept our thoughts (not fight them) and then learn to let them go. Release the power they have on us. If we can learn to release these and not ruminate on them, this will give us the space to allow more positive and supportive thoughts to come in.
Mantras can help with this as well (I AM worth a lot, I AM important, I have value). Saying these to yourself everyday over and over (even if at first you don't believe) can retrain our brains to believe it (and allow us to believe it). I have even wrote positive mantras to myself in my bathroom mirror so I am forced to look at these throughout the day.
Please remember to not be hard on yourself as you begin to attempt to change the automatic thought patterns. It took a while for you to get where you are and it will take a while for this change to kick in and feel normal. So allow the process to happen slowly and allow yourself to accept you as the amazing and brave person you are.
It sounds like you are trying to find a label to help you to understand why you are feeling the way you are feeling. Sometimes there are no labels for how we feel. Sometimes there is no name for the emotions that we are experiencing. Regardless, you do not have to continue to feel this way, no matter what you call it. If you are seeking to experience an internal calmness such as your external calmness, you may want to try some mindfulness practices or meditation. However, being able to get at the root cause of what you are feeling may be what you need to help you release this feeling for the long term. I recommend seeking support for this to allow this internal screaming to get some air and begin to breathe.