Totally agree with the above (especially the bit about exercise, gives your body a chance to do something with all those hormones and what not released from stress!)
Sleep is so, so, so important too, if you fall behind on sleep the real world will feel so much harder to deal with. Recently I went through a period where I realized I had gone for weeks with probably an average of 3-4 hours per night, friends were actually getting worried about me.. seriously the real world was actually feeling like coming out of a bad trip.. I was actually having trouble dealing with it. I had to just start canceling plans, cutting out anything i could cut from my plans. Real friends will understand (maybe reluctantly), if you are super tired and need rest, and they actually care about you. After a few nights the real world was getting way more manageable. And.. I started having dreams again!
Mixed experiences for me getting high when stressed. Not always bad for me , sometimes relaxing but... sometimes it just amplifies the stress. Sometimes it makes me numb, passive to the stress, but then a day or two later the stress comes back with a double whammy.
And yeah totally agree with phalaris.. I personally avoid caffeine when I'm stressed, it just makes me incredibly anxious. A bit more tired, but not feeling that horrible jittery nervous-wreck caffeine comedown is totally worth it for me. I actually notice for me anyway when I'm eating healthy stress doesn't affect me as badly either.. even if life is difficult at least my body doesn't feel so crappy or drained.
During that period of getting really tired, it was also an incredibly stressful period for me due to being way too busy, way too many projects, not enough time to relax, and also having events in my life that were hard to deal with and just felt out of my control. It totally put me in a headspace, and I guess I somewhat chose to deal with it like a trip, and just experiment and find what worked and didn't work for alleviating the stress.
Seriously though, good luck, this time of year school gets pretty stressful for a lot.. especially when it is on top of life and whatever else..!