Hi HJ,
I'd like to try help if I can.
First off, keep your eyes on the prize. The fact that you have taken on so much with a new job, college, your DJ'ing, furthering your self in other ways, is a LOT! Balancing all that is a very difficult task but just remember why you are doing it. To better yourself.
The problem people will have with you deep down is that they want a piece of that drive. I'll bet most of them are trapped in what they do and so strive to make you feel the same way.
The attacks you receive in your work place sound like a form of bullying. If you do not stay after hours, no matter what THEY say to, saying your not part of the team, ignore it. Its bull. The fact is YOU have a life outside your work place and they do not. It happens everywhere my freind and I know a list of such people.
So, this is the reason for the way they act towards you the way they do, in my opinion, and now a soloution ....
Do your job to the best of your ability.
Do your college work to the best of your ability.
Do your DJ'ing to the best of your ability.
Take pride in EVERYTHING you do because YOU have done it for YOURSELF. Not to fit in, not to please others. For you. If you go about this and remain humble in doing so the tide will turn.
Peace
Iain