You're 25... WAY too young to be worried about just "one" girl at this point.
WAY too young.
You should be worried about "Which one am I taking out on Saturday, A or B or C?"
It's just one girl and from what I read, she's not even worth it.
"hi I know u hate me
and I know u said I would try to contact u after we break up and of course u were right. u probably won't answer and that's alright. but I want to say I'm sorry. I very very sorry and sorry I'm being so selfish by sending this to you. but u didn't deserve what I did and I'm sorry.
be safe and have fun on your trip".
What the crap is this?
What in the BLUE HELL is this?
"Hi I know you hate me"
Really?
Look, apparently you are dealing with a 17 year old teenage girl here because it seems that she wants to get the last word in and yes, she's being selfish and yes, she's baiting you into talking to her.
Do yourself a favor, mate, STOP TALKING TO HER.
Move on. Get new girls, and forget this one. She's only bringing you down and causing you further insecurity issues.
Who the hell cares HOW she found out... she just did. It's one of life's mysteries and you might never get the answer. Forget about it.
And btw, any "friend" that won't talk to you again because of all of this... wasn't really a friend.
Rejoice, now you can make newer and better friends who don't know about this drama.