Sad thing is, if you had a tough time academically it will be very hard to transfer unless you drop down a few levels.
Have you reached out to the on-campus counseling center? They don’t like people to be unhappy, and I get the sense that you don’t know why things aren’t working out.
You mentioned summer classes at Harvard - do you mean actual college classes or pre-college classes?
Bad decisions are a by product of not knowing enough information. There should be a Dean of Freshman Students and others who can see if they can talk you through some issues.
I would say based on the prospect of transferring down quite a bit, and apparently no idea where you would transfer to, give UCB another try. If you can’t make things work, use the money you pay for college wisely and take advantage of all of their services.