Anyone else struggle to make good friends?

I’m in my 30s but I wouldn’t say I have a best friend or even anyone I’m close enough to to call on if I’m upset or have a problem. I meet lots of people because I’m in a sports team, work with lots of people everyday and have a group of friends, but I really struggle to become close to anyone. I don’t know if it’s me putting guards up or if I’m just someone that people tolerate rather than actually want to spend time with, but it’s pretty isolating. I don’t have any family I’m close to or could talk to and don’t have a Mum. I just don’t feel close to anyone. I’d really like to be able to move beyond this but I have no idea how! Anyone else struggle with this?