I'm currently in college (audio engineering / music business) and work graveyard shifts stocking shelves at a grocery store (yeah... NOT much money to be made there). Ever since I got into SCUBA, pretty much ALL of my non-rent money has gone towards it. I eat cheaper, dress cheaper, stopped drinking, don't go out with friends as much, stopped chasing women (that really hurt to say... but they cost a LOT, lol), ride my bicycle more to get around, etc, etc. Everything I do is with the intent to get me to my next underwater destination, more gear, and more training (I also would really like to get into tech diving... caves and going deeeeeeeep). SCUBA has total control over me! I'm at a point where I've realised that I really must focus on my future, and the fun and the women will still be there when I'm ready. I just want to hurry up and finish school, move back to a coastal state (Florida, I'm looking at YOU!), make a career for myself and earn a living so I can dive to live.
You're still very young (as am I), and our future is still way ahead of us. You have to ask yourself, where do you realistically want to be X years from now? Then, how will you realistically get there? I had a lot going for me for a while... then I've had some pretty big downfalls over the last few years (DUI and kicked out of college for not attending classes, to name 2), and you quickly see how hard life is without a 'plan'. Now that I'm back on track and moving full steam ahead, I can see my future again... and I'm pretty sure this is the only way I'll be able to dive the way I want to.
I don't mean to get all philosophical on you, but being just a couple years older than you, and somewhat seeing me in you, and already having gone through the downfalls... I have to highly reccomend a good plan if you want a good future. If you want to fast-track it to the good life, you need a degree (or already have a lot of money... which we don't have... so that leaves us to needing the degree to get us money). It's pretty tough and will be a long and slow journey to get anywhere without it. It really doesn't even matter what it's for... you just need it to get somewhere (and trust me, you can find SOMETHING of interest taught by a college... and the system ain't as bad as you think). Of course, anything is possible... but one road will be less bumpy than the other.
Good luck!! (to the both of us!) And hope to see you on a tech liveaboard one day