I fully understand how that experience sucked, I honestly do.

You're obviously an intelligent guy, getting into Uni, so I'm assuming you're aware that depression can be caused by a chemical imbalance, those antidepressants could help you a lot buddy. You need to see a different GP, you can find one who will be more understanding. This could be a life changer for you seriously, not just regarding tomorrow, but for the rest of your life, surely you owe yourself that chance. Genetics can also play a part, and from your parents history you've mentioned, this is important. Top all that of with the struggles at Uni, and you're general wellbeing, all of these factors would make the best of us feel exactly the same, you aren't a lost cause pal, you need to see a GP and further professionals that will show you more empathy, they are out there for you, regardless of that poor GP you saw.

You show glimmers of hope in your own comments that you've posted, when you've said yourself, that you know things could get better. Only a year and a half ago you had a happier period with your girlfriend, I'm sorry to hear that relationship didn't work out, but that doesn't mean that happiness won't come again, and you can return to those happier times.