I'm a year older and feel myself sometimes as will I be on my own etc. I think these are natural thoughts.
First question here. Did you find out if she was cheating? And who ended it?
You won't forget easily, but you've done great doing the blocking. Social media makes it so much harder.
One thing you could do is join a gym, maybe find a club or something. Sounds mundane, but keep yourself occupied.
The biggest thing is don't rush into something because you are lonely. I've done that and it doesn't work out well.
Just put yourself first and hang in there.