My girlfriend F18 was SA’d last night and she seems to be okay with it and im 18M in tears. Am I insane?

I apologise for such a brutal title. Me (18M) have been going out with an 18F for a long time now and she was my first everything. She went away a few days and told me that she would have to be away for a month, and that she is terminally ill and needs treatment out of town so she’s staying with her grandparents and im guessing her grandparents wanted her to socialise, so they brought round friends of theres and they have a son who is 19M, She was sleeping in her bed and he came up the stairs and he spread her legs and she shouted stop and you can guess the rest from here. This is absolutely soul crushing to me and im going through so many emotions idk what to think or feel and she seems to just be okay. Help me