Me and my girlfriend just broke up. We're both 17. We were very close for years and had both wanted to date the other for 3 years. We lasted a month when it finally happened because my problems got in the way. I screwed this all up. I've always been one to care about someone a lot in a very short period. Dating just intensified that caring feeling I felt for her. And now it's just done. I'm done

You're 17. I don't mean to sound preachy, but you've got a LOT still to learn and experience. I totally understand the feeling of being entirely "done", but often times people who say that go right back on the road towards healing in no time.
I am terribly sorry to hear you two broke up, but perhaps you can try to just be friends for now; that way you can still have a line of communication open should either of you want to give the relationship a second chance.

Unless you both feel you need time and space. If so, take all the time and space you need. In the meantime you can ask yourself internally a few of these questions :

a) Did we break up for a good reason?
b) Was it a mutual break-up?
c) Was there communication throughout?
d) Am I ready to be on my own for however long it takes to heal?

Best of luck.

"I've always been one to care about someone a lot in a very short period of time."

So you need to figure this out so you can learn from this experience and prevent mistakes from happening again. Life is a journey and we are constantly learning from things that happen in our lives. So you are 17 and not done. You will continue to learn from this experience and many more.

Get to know someone well while you are talking to them, dating them, spending time with them, etc. Professing your love for the person after one date could potentially scare that person away. That is going way too fast and will only hurt you in the long run. Plus it appears to the other person that you are very needy. Learn from this and take it slow next time. We have all had breakups and we have all survived.

Please don't beat yourself up about your problems getting in the way or you screwing things up.

Fact is 97% of first relationships end in break up. You just joined the club. Lots of good members.

You are not especially bad. You're just normal.

Knowing someone for years before deciding to date them actually lowers the chance that it will succeed. Friendship and 'romance' are not usually found too close together. My advice; keep them separate.

Men ruin their chances with women by being overly kind, compassionate, caring etc... That puts you into the 'friend' category which is nearly impossible to get out of.

Women lust after the 'bad boy' and that pisses nice guys off. It needn't. Being bad is just a matter of chasing a flirting with a lot of girls. Don't fall in love before you've even dated her. Be romantic in your pursuit, but make sure she knows it's lust, not love.

Part of being a 'bad boy' is being self sufficient. Don't be too broken up about this girl or that. Be too wrapped up in your bad hobby such as skateboarding, bmx, or other extreme type sports, or regular sports like football or basketball. Being self sufficient, busy, but subtly flirty will get you some attention.

Hope it helps. I learned the hard way, and then the harder way.