My friend, dating people to keep yourself from feeling lonely is extremely unfair to the other people. You can't expect another human to fill a void in your life.

There's a lot to unpack here. It would be irresponsible of me to say anything with certainty, but I have a strong feeling you're dealing with Depression on top of having not properly mourned your breakup. I know from my own experience a really bad breakup can make a person feel like they'll never find love again and it can really wreck a sense of self-worth. I'd look into working on those issues first before dating anyone else.

Because you do deserve to have fun on dates, but you gotta at least be doing it from a healthier place.