Alright Girl. SNAP OUT OF IT!!!!!!
Look at this way, let's say you and A start talking on a regular basis again and starting hanging out, etc.....I promise, feeling this way is not the start of that process! If you feel this way it's going to show and not just to him.
Get up, get out and get some for you!!! Go do something for you!! Start GALing RIGHT NOW!!
Yes you get to be sad, but you also have to make time for happy. So hop to it.