I met you and Jason at the London meetup and you two looked like you were having a lot of fun. It's easy to have an opinion with hindsight, but it did strike me at the time that there was something slightly unbalanced in your relationship, that one of you had more power than the other. But some relationships are like that, and I didn't know you enough to judge.
As for the rest, I agree with Billy: take some time off the boyfriend business. It was a long relationship and you were —and still are— quite young. This relationship is bound to have some influence on you for some time. It's normal to feel lonely and dejected and depressed. Take the time to find yourself, to discover your true values again, and not what he wanted you to be, or what you thought he wanted you to be.
Best of luck, John. You will find your path in life, through your studies, your family and your personal goals. And love will come along. You deserve it.