I would say it would depend on the college you go to, but over all, it is far better than high school. Remember, folks HAVE to go to high school. They DONT have to go to college. So most folks take college to better themselves and know it's somethign that should be taken seriously. That being said, you will have some cliques--I avoided most. It helped that I didn't live on campus but nevertheless I had to deal with it sometimes. But I can say I was never attacked or ridiculued like I was in high school.
As for work and activites, I did have a job all 4 years during my college years, and I never had a problem b/c my job was flexible. I had between 13 and 18 credit hours for school and about 15 hours of work. I could handle it but some folks get overwhelmed. If you're unsure, do school first, then add in work or activities as you see time. You know you best. If you're an early bird or a night owl, you'll be able to get what you need done.
My best advice is to have fun, try to relax, and don't worry the small stuff.