Girlfriend kissed other guy....help!

I'm sure we'll find someone eventually, il speak to her tonight and show her the door, thanks for the reply.

Hi, I've been with my girlfriend for some time now (we're both 17) and things for me were in my head really starting to pick up. But I get home and all my messages are being ignored so I send more, then I get message from her mother saying we're taking her phone, I ask why and I get told she went to the cinema with another guy and they kissed, I feel completely let down and upset, she said she still likes me but I can't stop thinking that if I've done something wrong but her parents have invited me over for the weekend to talk to her, does anyone have any ideas what I should do? Thanks.