My girlfriend and I have been dating for about 7 months now. We were good friends for 3 years before this, so we do have some history together.
I am a science student and so getting to know that my research work would be shown in what's the most popular science magazine in my country meant a lot.
The head of the state would present it to me in front of some journalists and dozens of other important people in a 5 star hotel. So this was a huge thing for me, probably one of the highlights of my life.

I told my girlfriend this, she wasn't too excited but she told me she would join me for sure.
I had even gifted a dress she loved but couldn't afford. I told her even if she came for a few minutes it would mean a lot. My parents are no more too, so I didn't really have anyone else to come.

Phones were to be switched off during the main event so I did just that. The whole event passed and my girlfriend was nowhere.
When I called her later she just told me she was on her period and I was overreacting. She was apparently group studying with her friends. I obviously trust her on this since we have that kind of relationship.
I told her I was upset and she told me I didn't get her pain and I needed to be more sensitive of her issues and she didn't expect this from me.

I honestly just hung up on her at that point. I need some time to introspect.

She thinks she didn't do anything wrong, I think I am in the right.
It's confusing...