AIO in the way I responded to my girlfriend?

My(21M) girlfriend(18F) and I have our exams from tomorrow. While I am having my year end examinations, which if failed, could make me detained for a whole year, and she is having a part-yearly examination. I always try my best to be on call with her while I study, but it becomes uncomfortable sometimes because I have to hide her face during the call, and she constantly interrupts during call, which breaks my flow of study. I was cool with it, but after I told her I can't study with her for 3 hours, she becomes angry and thinks I'm being inconsiderate not being with her during this "stressful" time. She is getting stressed about her exam, and because her ex who she is best friends with, is not talking with her(Before you tell that's a red flag, no she is not missing her ex or anything, she was best friends with her ex for a long time, so when he avoids her, she doesn't feel okay). So, how do I settle this? I really don't want her to mistake me but I end up hurting her.