Which iOS do you have? Camera Roll was gone for awhile on iOS 8.1 I believe but it's back now. Try the usual (reset) to see if that helps. What happened right before you noticed the camera roll gone.
It's been gone for a few months now. I've just been emailing photos to myself, but that is incredibly frustrating when they should be automatically showing up on my computer in my Photo Stream. The current iOS is 8.4.1.
Not seeing any reported problems with Camera Roll in iOS 8.4.1 but it sounds like you were having this issue before 8.4.1. Did you reset (hold lock key and home button until device reboots) to see if that helps?