Single getting me down

Hi all,
I was wondering if I could get some advice. I am a 23 yr old female finishing up college this year and working part time at the moment. I know this sounds absolutely ridiculous to be writing a thread about but I am really down about being single.

First of all, I know I am young and have plenty of years ahead of me but I can't help but compare my life to all of my friends and family and to feel inadequate. I have wide groups of friends and I am the only single person in each of these groups and it has generally always been this way. A lot of my friends have been in long term (6 yr) relationships with their boyfriends with some of them being a lot shorter. I have never had a boyfriend although I have had past 'things' (I feel like in this day and age it is very hard to actually label anything short term a relationship).

This has started to get me down as I feel like there is something wrong with me. I feel like I am defined by being single regardless of the fact that I am good at my career and really academic in college but the first question I always get asked is 'Any boys?' or 'Why are you still single?'. I don't know what is wrong with me to not have anyone on the scene. I went through a few years of being heavier than I would have liked but in the last three years I have really worked on this and have managed to become OK with how I look (albeit I wouldn't say no to a flat stomach!).

I read some of the threads on here and I am afraid as I don't want to go through my entire life single. I don't really have hobbies but I do go to the gym and then I work a lot too and socialise at weekends. I feel like I meet great guys in nightclubs but they never bother to text the next day. Is there any suggestions on ways I can meet someone or things I can do to sort myself out? I do have tinder but I think it is a waste of time.

Thanks in advance