How do I reduce my stress level NOW?

I am working full time and taking college classes and don't have much time to exercise. I can't quit my job, I can't drop any of my classes, and I do get an adequate amount of sleep. How do I reduce my stress level now because little things are starting to piss me off and annoy me that didn't bother me before.
The reason that I ask how can I reduce it now is because I can't deal with how high my stress level has gotten and I can not wait til December to relax. I have had a full schedule before and have never been this stressed out before and don't know why I'm getting all stressed and irritated now.