Long distance relationships...?

So I'll try and make this brief. My boyfriend stayed with me for a week and then he had to go back home, two weeks later I flew to Florida and stay at his house for another week and I just got home 4 days ago. There's a big distance between him and I, probably more than a thousand miles (i live in Vegas and he lives in Florida) and I'm just scared that things might fall apart. I asked him if he was sure about doing this and he told me he was positive, but I know guys are very indecisive and they change their minds like girls change clothes. I'm afraid that when school starts things are going to change drastically, I know I'll be able to see him in December,January, March, June, and July but it'll only be for a week or two. and even I know that after awhile that wont be enough. He is an amazing guy, he treats me with so much respect and he likes me for myself. I know that most people will tell me that long distance relationships don't work but I knew from day one that i wanted to be with him and im taking my chances. But more than anything im afraid of losing him. I need some advice, tips, whatever you can give me! im in dire need.