I'm in love with my best friend

This is tough. Perhaps he is feeling the same way. Being drunk you say lots of things, lots of stupid things that's for sure. But if he has said it twice, perhaps he means it? It is true that relationships can possibly ruin friendships as you both become quite dependent on each other in a different way. I would say talk to him about it, but that would make things a little more awkward as you'd expose the idea into the friendship. My advice would be to keep it to yourself for now, see how the next few drunk nights go and take it from there. I think it would cause damage to expose the idea into the friendship as you might not know how he would react.
It generally becomes the case that if you are very close to a particular person that these feelings may arise, however, if you want to keep it strictly platonic then raising the idea of a relationship would be the last thing you want to do.

Do you not want to be in love with him because of what might happen, or because you want to keep it platonic?

This is killing me.Okay, so I'm a girl and he's a boy, we're both 17 and we are best friends. We've known each other for four years and I would seriously give my life up for him. I tell him everything and we have a lot in common with our family's problems etc, and I trust him with my life. Likewise, he trusts me because he's told me stuff that (apparently) no one else knows. Anyway, I thought for most of our friendship that this was just platonic caring for my best friend, but recently I've been feeling different. Twice in the past two weeks, we've been drunk together and he's told me how much I mean to him. It's quite obviously platonic but the fact that he vocalised how much I mean to him (which neither of us would do while sober) really knocked me for six. I now have the utter urge to see him constantly - I did before but now it's slightly different. I get the urge to hold his hand or just hug him, when normally both of us are made uncomfortable by physical contact and I would never have had this urge before. It's killing me - I see him almost every day because he goes out of his way to see me (we live about half an hours drive apart and he always drives to see me) and each time I do I feel worse. I love him to pieces but I don't want to be IN LOVE with him, which I'm scared might be happening. I just had to get this out of my system because I can't tell anybody. I've never had such a good friendship and I would never want to ruin it.

Because of what might happen. I genuinely feel like he's my soulmate (cringe, I'm fully aware things may be different in years to come) and I wish I could either stop feeling these things or that we could skip over the awkwardness of expressing our feelings and just know where we stand with each other.

I feel like I could've written this myself. I know how you feel!