Please give your opinion

So my girlfriend and I have been together 2 years. We have sex around 2-3 times a week and we are very careful about it. I use a condom and pullout method everytime and she is on birth control. She had her period a week and a half ago. However this past week she has been pretty nauseous. Not feverish. Her head occasionally hurts, and so do her breasts. I’m not sure if it’s the hormones from her pills causing these symptoms, but I am freaking out a little.