Do I have a right to be pissed off ?

So I have this mum friend who lives near me. we used to hang out a lot until she split up with her baby daddy and started getting dates every week with different guys and started dating a guy. I didn't really hear from her unless she had an argument with the new guy or they broke up. They eventually broke up due to his mental health and she started dating again. I went out clubbing with her and her friends, I told her I have bad social anxiety when it domes to new people and the sort of club music wasn't my thing. I was at the bar and then her mates and her grabbed each other and went off, I was left at the bar for 20 mins and then I decided to leave and go home as I felt I was going to have a panic attack I came home to my partner and had a panic attack. She didn't ask where I went until the morning and she only came in to her house around 10am. She said sorry she doesn't think it's that deep so I was like fair enough. I looked after her kid once baring in mind I have 3 under 3. She went on a date and I said I will stay until 10pm as my partner has work and youngest still wakes up for feeds. She didn't come home until 1am and didn't tell me as I fell asleep.she said sorry and I was like okay. Few months later I told her we are going to Thorpe park for my birthday, she said she is definitely coming etc. I told her 3 months in advance to find child care etc. coming up to my birthday she met a guy weekend before my birthday and I said are you still coming and she said yeah defo. Then a few days she doesn't have childcare for Saturday but Sunday as she's going on a date. If I want her there could I look after her child on Sunday and then ask her auntie to look after her kid Saturday. I said no it's my birthday weekend and she said as I can't find childcare for Saturday. So I said okay that's fine. Anyway on the day of my brithday she sent me a Snapchat of a creamfields ticket, she's decided to go creamfields?? I was very annoyed. My partner wasn't happy as I told her in advance and she's only met this guy and found childcare for the Sunday but not my birthday if she's meant to be a close friend of mine. She keeps asking me to look after her child so she can go out partying/dates with her new boy and her friends birthday parties. I agreed to look after her child tomorrow so she can go to an event for her friends birthday. I'm still annoyed at her but tbh we haven't been talking. We've been sending snapchats of thinks for the streak but nothing else. I don't know how to say anything I'm not very confrontational when it comes to these things also I don't want to fall out with her as my children love her child.