How do I stop my fear of loneliness?

This post might be a bit longer and can get a bit confusing because I'm mostly just writing down my thoughts and realizations.

I'm 26m, currently working a 30-hour week with a sufficient income. I also feel like a total loser. I think this stems from mainly 2 reasons: One reason is that my income albeit sufficient is not a lot, especially for my conditions. The other reason is that I have never had a girlfriend or anything even close to a romantic or sexual experience. Both those things bother me a lot but if I was 'healthy' they shouldn't.

The low income is something that I don't feel should bother me. I get enough so that I can decide to only work 30 hours a week. I can also save up money to go on vacations yearly and also afford bigger things long-term. And yet my income makes me feel inadequate. Because a lot of people comment on it being so low. It feels like my desire to get more money is externally motivated instead of something that I want for myself. Not having a girlfriend feels more internally motivated. It just sucks not having someone to hold me or to cuddle with.

These 2 things leading to me feeling like a loser indicates an underlying problem for me. I am afraid of being perceived as a loser. I think that this comes from my fear of being lonely. I don't want to be left by myself. Currently this leads to me trying to connect with as many people as possible for me (which is not that many actually because I'm bad at making connections). This is also an overcompensation for my last few years of being lonely. What I noticed is that I cannot be on my own anymore. Whenever I'm sick or injured and can't fill my evenings with sports, I feel so much worse. While I do think, being in a group is more fun, I shouldn't have a near breakdown every time I'm alone.

I also worry about what other people think of me constantly, get jealous easily, and I am not a very confident person. I think all of this has to do with pleasing people so they like me and don't leave me alone. And I just can't stop it. I don't know why I am this way. I don't remember anything in my childhood that was personality-forming in this way. My parents are loving. I had friends. I wasn't bullied. If there is some trauma, I don't know how to find it.

Another thing that I perceive as a very annoying characteristic of my own is my constant desire to be better than everyone else and getting dejected when I'm not. I'm not sure how this ties in with my fear of loneliness.