I keep waking up at the same time every night? Why is this? 10 pts?

This past week I have been waking up at 4 am EVERY night without fail, and i also keep having these weird dreams. I guess i dont mind but it wakes up my bf...i was wondering how i could get rid of this? I'm perscribed xanax adn prozac...would it be unwise to take the xanax before i go to bed? i know i'd sleep well. Please help me out? ty