They don’t already have their friends. Everyone is in the same boat as you. You need to give it time. My kid had a hard time adjusting last year and this year, she can’t wait to go back. I PROMISE it will get better, but not immediately. If you aren’t happier by the end of October, come back to us. But I am very sure you will be fine. Meanwhile, participate in as many activities as make you happy, but leave time to relax too. Leave your dorm room open. Read bopper’s pinned post on how to make friends. All your feelings are natural and normal. And forget about guilt, it’s a useless emotion.
Btw, 2 hours is no time at all. What were you doing 2 hours ago? If you really want, you can visit your family, but I would try not to yet. Your high school friend will be fine.