I'm in college myself, I'm just starting my sophomore year this fall, about an hour's drive from home. I also left my horse in the care of my younger sister and my dad. I suppose the best advice I can give you is to relax and know that all will be fine. I would say spend your last day at home with her just being buds and bonding. You can always
call home and get a "Horsey report." I probably irritated the heck out of my family, lol. I also found it helpful to take photos of my horse with me, along with pics of my family and friends, and hang them on the wall over my bed in my dorm. I also saved a bit of my horse's tail hair that he stepped on and yanked out of himself and took that with me.
I can almost gurantee you that she won't be taken care of exactly the way you do it, it's just a fact that everyone does barn chores a little differently, but I can also almost gurantee you that when you do come home, you'll be greeted by happy nickers and whinnies. It will be different, there will be a little "equine withdrawal," but the world won't end, and she's still your horse, no matter where you spend the night
I hope that helped, and good luck and have fun at college!