Hard to give advice without knowing the full background of what you did to make her act this way. I’m not asking for the information as I assume that’s personal and you’d rather not say, but it makes it tough for me to say whether or not you can completely condemn her for blocking you.

The way Facebook works people who “you may know” constantly show up in your newsfeed. It’s possible, from her perspective that seeing your name brings up bad memories she’d prefer not to think about. She might have just blocked you because she just wants to forget.

No matter what it’s true she doesn’t see any reason to reconnect with you. Which is unfortunate, considering how much you want to clear things up. But, as others have said, the best thing for you to do is to just forget about it. Closure is a rare thing. Fretting over it isn’t going to help you. What’s happened happened, move on.