What do you have/how long have you been out, if I may ask?
It's funny that you bring this up, because I was just suffering from something similar. Last friday, I tore some rib cartilage and I've been just sitting around.
I also act like a very different person. My temper gets REALLY bad, I'm extremely irritable, I find myself struggling to cope with daily stresses, I can't pay attention or remember things for the life of me, I can't sleep, I get lethargic, and I overeat. It was getting to the point where I just couldn't handle it anymore, so I went just went in and trained yesterday.
Usually when I get injured, I just try to work around it. It's often inconvenient, but I prefer it to just sitting around and going crazy. If I'm sick, I usually just take a day or two off, then go back in. But it sounds like you're in a position where you can't do that, so I would probably do what others have said and shadow box a bit.