I'm not someone who does computer engineering, but I'm doing masters in Astrophysics and we have a fair bit of programming/computing. From my experience, it's not so much about the maths as it is about you just playing around with whatever software package you are working on and being patient. But yes you do need to be decent in maths as well since that does help in learning a lot of program logic, etc. If you already aren't used to it, I'd highly suggest getting used to a command-line interface such as Linux.
As for if you will have time left for gaming, that depends on the course. For me I normally don't get much time to game on weekdays at all. But on weekends I can sneak in a healthy dose on gaming without too much troubles. But I do carry my handhelds to and from uni, so that's some extra gaming time. Don't let gaming set you back from a good career you may be interested in.
