<human>: Condense the text into a few key points

I am very much so in love with my girlfriend but she can react poorly at times when she doesn't get her way, becoming almost a different person. I try to calm her down but she doesn't listen and if I don't give in she will get mad at me.

A few days ago she had told me that she wants me to go to a country concert with her and when I said that I wasn't able to she began telling me that I could do it but I just didn't want to make the time for her and she became angry and sad over the situation. When I don't give in she always has reasons that I should do what she wants and she becomes upset at me for not giving in.

This is something that has only happened in the last two months when she became stressed because of finishing college. I just want to find a way that I can get her to see that she shouldn't get so upset or use raw language to try to get her way without hurting her feelings.

How can I treat the situation as to not upset or hurt her (while she is still struggling with her own health) while still showing that it is not okay to act like that?
<bot>: How do I tell my girlfriend that the way she acts when she doesn't get her way is unacceptable without hurting her feelings or damaging her already hurt mental health?