Your feelings are truly understandable but at times, we scare ourselves away from a situation too early or too instantly. It's only been one week into uni, I'm pretty sure your mind hasn't even fully accepted that you're in uni yet - Keep the door of switching out open for yourself. Nothing is ever the end of the world. I didn't like Mac at all in first year but soon after, I fell in love with it and now the thought of leaving it forever scares me. It's truly been home. I also did wanna switch out to a uni where I had better friends. Things certainly do change. Best thing about uni is you can just be, be yourself. If you are into interests/hobbies you'd like to pursue - go ahead - no ball of chain around your feet. Be active. You'll make a variety of friends. Remember, you didn't make best friends in one week into high school either.
I feel in first year, a lot of people are looking to make friends anyways so be more open and receptive. I know if you stick it out, soon there will be a time when you wouldn't even feel like going home