When we are feeling low, it is easy to see someone else, especially an ex, and believe that they are having a great life, doing all sorts of things, and moving on while we sit and "watch"---facebook, remember, is only what a person chooses to show to others...
And, yes, you should block her if you have to, for your own good. Not that you won't think of her and still have those feelings, at least for a time, or now and again for a long time, but it will be healthier to distract yourself from them rather than to immerse yourself in that "place" where she is "up" and you are "down".
Your posts have shown both intelligence and humor---I know humor often comes from a dark place but it is a wonderful gift, and coping mechanism. Take care.