So, we got a whole new management at my work this summer, including my supervisor who I like at the moment. It's something more than like. Anyway. He's 21, I'm 18. The first time we worked together it was easy to be with him, I liked it.
As of lately, we have gotten extremely close. We'll go to the movies together, we'll go to parties together, we'll text a lot throughout the day, and call each other. At work we're always talking, and giggling, and we have a lot of physical chemistry, I notice that we're always near each other, he'll hug me, or hold my hand, a lot of little things. But I feel like we're at that level of friendship too, because he has this "friend" who he wants to hook me up with but he hasn't. My friends say that he's my boyfriend without the physical stuff, he's constantly buying me little things, and vice-versa
He is moving 10 hours away to finish his degree in engineering in July, and he plan on visiting me, and has already asked me to go visit him as well.
It's a weird situation where the pieces fit, but it's hard to put together, and I really do not know what to do anymore, because I feel so much for him but I can't really do anything about it.

Tell him. After all, you will have to do it sooner or later. Communication!! One of the biggest parts of a relationship. If in doubt, communicate.

Yup, it sounds like you are already together.

Before you invest your feelings any further, really think about whether you will be able to handle the long distance relationship... if it will be worth it.

Long distance relationships aren't for everyone... and it takes A LOT of work. Make sure that you're thinking things through.