don't know what to do with this girl?

[465]

Ive been dating this girl a couple of months and it was all going fine until we were supposed to go to the cinema but she ended up going with her friends and didn't tell me.

She was ignoring my snapchats and messages for a couple of days. Then I added one of her friends on fb because i knew him from ages ago and she messages me asking why I added him so I told her and she just replied with "sure".

I snaochatted her today apologising and asking if we could get over this, this was after like 4 days of no contact and she replied 20mins later saying she was going out and to ignore any drunk texts with nothing about what I just told her

She seems super p*ssed off with me and I have no idea why, what should I do? help?