my love life currently sucks ass.

Sooo my love life currently sucks and I guess I'm just wanting some advice because I think it's just me being scared to actually try anything new with a new guy. 
I dated this guy for almost 4 years on and off. He was the love of my life, my first everything, and I thought we would last but I guess I was wrong. We pretty much completely cut things off at the beginning of this year. I stopped hanging out with him, talking to him, tesxting him. All of the things we agreed we would try to do because we ended on good terms and wanted to remain in each other's lives. 
Since then I've tried talking to new guys but every time it seems that a guy is going to try to make things official or get closer, I shut it down real fast. 
I don't know if it's just me being worried about what could happen, or maybe that those guys just weren't for me. I feel like a total bitch for shutting them down like that but limenwhat am I supposed to do if they don't make me feel happy? Pretend that they make me happy? Should I just go ahead and try to date them..? I just feel like I'm stuck in a place I don't want to be. I always find myself comparing these new guys to my ex and I know that isn't right but it's just hard to find someone who makes me feel the way he did.. 
I just want some advice on how I should be dealing with something like this please! 
❤️