Keep busy for the first couple of weeks.
Play "I Will Survive" and "Before He Cheats" as many times as you need to in order to feel empowered.
But then take some time to learn something from the relationship. Think about it, how it went, what you did, what he did, what made you start coming to the realization that he didn't respect you, what you did to try and fix it, what was his response and so forth. What you learn from relationships when you are young is what you will and will not tolerate....what are your "deal breakers". So many young girls these days seem to take a lot of crap from boys and I always wonder why???? And remember that it is easy to start seeing the relationship with rose colored glasses after a few weeks apart, and forgetting all the negative stuff that precipitated the break-up.
So, you pretty much have to hang on for 3 weeks and then you'll be at college and a whole new world opens up and this guy will be a distant memory.
And congratulations for recognizing that it was not what you wanted & getting out of the relationship instead of taking what he was dishing out.
When I was your age I was dating a guy for all of my senior year of high school. The "love of my life" at the time. Around May, he decided to weird out on me, didn't call too often, if he wanted to go out he'd call at like 6pm on Friday night, which of course led me to think that he had talked to all his friends, nobody had any good plans, so I was his 2nd (or 3rd or 4th) choice...kind of like "I have nothing better to do so I'll call her". Well, it happened for 2 weekends in a row, and then I broke up with him. Told him I had no intention of being an afterthought and that I expected to be respected and since that didn't seem to be his thing anymore, we should go our separate ways. Shocked the crap out of him...I guess he just figured that he was such a catch that I'd put up with his crap.

Of course, all my friends thought I was nuts, as it was about 3 weeks before the prom. He even said "What about the prom? You'll have no date". I told him that I'd either not go or go solo, but I wasn't going to put up with crap to have a prom date. Well, about a week before the prom, he came around, apologized, actually had a lot more respect for me because I had respect for myself. We did end up going to the prom and dating for the rest of the summer. Then we went off to college and went our separate ways.
A funny addendum to my story...the next summer I was in a local bar and this guy comes up to me and starts chatting. I chatted with him for several minutes and he finally said "You have no idea who I am, do you?". Nope, didn't. It was "the love of my life" from my senior year! He had grown a beard and I didn't recognize him. That probably wasn't too good for his ego.
