I'm older and just experienced heartbreak

Ouch. Losing someone you love hurts so much. We all long to be loved and to love and to have that experience and then lose it is awful. While it is easy to feel angry or start doubting yourself under these circumstances, I would encourage you to recognize the agony of what you are experiencing as an indication of how much you value loving relationships and how much you want to make this happen in your life. When we are going through this kind of loss it is really helpful to have the support of friends and family. While no one is going to be able to make it better, we don't have to be alone with our pain. If you are not comfortable with going to those in your life it may be a good time to see  a counsellor to help you cope with your distress and learn how to move past this and find the love that you are looking for. 

Hi, San Diego. I'm sad that this was your first experience (in 25 years) with feeling in love. You deserve better. My understanding of today's (western?) social cultural norms is that it is somehow acceptable to abruptly stop communicating with someone you've been seeing, without explanation. I don't get it. It's rude. You're better off without this person around. There are still people who operate with respect, but this person isn't one of them.

If I'm reading this right, you knew this person for a week? In my humble opinion, much heartache and many poor relationships come from attaching too soon. It takes years to get to know someone deeply. I know it's hard to keep yourself from falling in love, but you owe it to your heart to take these things more slowly, because everyone puts their best self forward at the beginning and it takes time for that to relax and for you to see who they are when times are tougher and real stuff happens.

If I was your therapist, I'd be curious about how this is the first time you've fallen in love? Or is it that you were in love 25 years ago?  Was your heart broken then, or did something encourage your heart to close? What has kept you from either meeting people or letting yourself fall in love until now? Is there a danger that you will decide love isn't worth the risk? This is a crucial time for you to potentially seek professional support from a therapist in order to understand yourself and not shut down, if that's what happened before. :)