I've been on Yaz for about 3 months now. I took it very rigorously on the first 2 months, always at the same time. But this month I started University and I started taking the pill whenever I remembered sometimes in the morning sometimes in the evening (but I NEVER once missed a pill). I had sex last Saturday with my boyfriend and we didn't use any backup protection and he didn't pull out... what are the chances of me being pregnant?

There is always a chance of getting pregnant when you have sex. Birth control lessens that chance. Taking it incorrectly increases that chance, but I think you're reasonably safe. I would find a good time, set an alarm even, to take them while at college. Just to be safe.