I'm really sorry this has been your experience!
Honestly there are a few problems:
1. You could be choosing the wrong guys. Because you are watching the people around you and what they are doing, you are not being picky with men, and that could be why you keep getting disappointed in the end.
Question: did you have sex with the guy that blocked you?
2. Maybe it's something that you give off. Maybe you are showing them your thoughts - that you are desperate for a boyfriend to show off. Honestly in this society it is really easy to want to keep up with everyone, but when you start dating someone, just keep it to yourself and aim to maintain your privacy and let the relationship grow naturally without trying to become 'exclusive'. That will happen naturally.
3. Maybe you lack confidence, so these guys ( even the ones below your league ) don't value you or respect you.
It is important to work on yourself before jumping into a relationship, because something as simple as your own personal self esteem could stop the relationship from progressing.
4. In terms of online dating, you are not really the catchment group, and therefore the likely hood you you finding someone your age, near you, etc is low. Try something like Tinder. Here there are loads of young people ( although it is known for hook ups, you can filter those people out ).
5. Go out more. It seems to me like your life is repetitive, and if you went clubbing, to concerts, or random parties ( there is an app where people post their parties and people just turn up - but always go with someone!!)
6. Always maintain your hygeine. Maybe that is the problem and you just don't know it.
7. Also maybe wait a little before having sex. You want to filter out the guys who want a hook up and the ones who want to get to know you.
Also one thing to remember is that you can be happy without a guy. Once you find comfortability yourself and your singleness, and still happy, then the right sort of people will gravitate towards you.
Lastly, don't look at your friends with kids and see a rosy picture. Kids are a nightmare, so don't be quick to get pregnant thinking it will maintain a relationship.
But also make friends with other single girls, because your current friends aren't that relatable anymore.