If you're not enjoying it you don't have to do it. I switched course (admittedly from maths w/ CS to pure CS) after my first year and had a much better time.
Get involved in stuff. Don't spend all your nights indoors hacking!
Yes, be flexible. I started out in Computer Engineering, and was miserable for 1.5 years. After switching to Computer Science I was much happier as it was a better fit for me.
Get involved in stuff. Don't spend all your nights indoors hacking!