Why am I so stressed

I have been trying to figure out the reason that I am so stressed. . .I don't FEEL stressed, but my body is telling me otherwise.

I have come to a couple of conclusions. The first being that the past few weeks have been stressful because of the roommate situation. It has been nice this week because the 2 of them are gone. . .well the one roommate and the one guest are gone. I don't know how to take this but I don't want to be stressed while living here. What to do? I'm thinking about having the roommate make good on the promise that her guest will only be at the apartment sporadically until Jill moves out and we have another room available. I know she will probably go into a rage but I really can't handle the fact that it has been this long and I was walked in on in the bathroom on Sunday morning. . .the door was shut!!!!!!! (the lock on the door doesn't latch.) Communication is key and since there hasn't been any. But DUH!!!

The second stress conclusion is that I haven't been able to work as much overtime as I need to.

I'm not sure what to do about the first problem other than move which isn't an option. I have started to be better on the overtime though. Just thinking about the roommates coming back gives me a headache. . .What do you do?