So my friend was having a dance for her birthday and I was s

So my friend was having a dance for her birthday and I was supposed to be her best friend in it.
Every dance practice I went to, I got irritated beyond reason (It's part of the depression and anxiety) and I never used to be like that. I would get immensely frustrated because the instructor only spoke Spanish and I could barely make out what he was trying to tell us to do. It was just a long struggle but worth it because it was for her.
I then missed one day because I was spending that day with my family, and I had gave a week in advance that I probably could not make it. They had also changed the schedules and they said it was changing to Sat/Sun instead (Sun was the one day I was going to miss), and I said I have to ask but I'm pretty sure I can fit my schedule to change from Mon/Tue to Sat/Sun. Then I told then I could. Well I went that Friday AND Saturday, and then also reminded my friend I would be missing Sunday. She called me late Saturday and said if I did not make it that I would be kicked out. So Sunday of course I miss it and I find out yesterday they did kick me but for different reasons. They said it was from my attitude (not to mention that my friend and her brothers attitudes were greatly worse than mine, not even kidding) and also because I apparently went off on her mom. I never once went off on her mom, her mom was really sweet and helped me go through everything and calm down. Plus she's an adult, I wouldn't dare disrespect an adult like that.
I've been trying to explain to my friend that irritability and my attitude was from the depression, because I never used to be like that at all.
This is causing me a great deal of stress, and I don't know how to explain this to her and her family because they're *less educated* so they don't know very much concerning matters like this. It's came to the point where I don't even want to be friends with her anymore.
Help, please? Any tips maybe I could use to help explain this to her?

It seems unreasonable, but honestly I would take the high road and apologize to her and her family and say you really couldn't make it due to a family obligation. If she can't get over it, wish her well and end the friendship. Hugs!