<human>: Give me a shortened version of the text

I was doing a workout at my college with a few of my friends/teammates. We were doing core stuff on mats just outside the fitness center when two girls walked by. One of them said to my buddy, "Do you even lift?!" (Jokingly)
He said, "yeah, do you even lift?!" 
Girl: "Nope! We skipped our workout!" 
Me: "I can tell" 
My friends were like oooh and stuff and the girl heard it. I didn't understand what she yelled back until later but they said she said "Literally fuck you!" 
I yelled back I'm sorry!
My buddies were laughing and joking around calling me a dbag and savage ect. I felt bad but didn't think much of it. I would never mean to offend anyone and my intent was just for my close friend to hear me for a laugh as like a gainz joke. I got changed and went to the cafeteria where some of my friends and some girls were. (offended girl wasn't there) They said "douchebag you can't sit with us!" I wasn't sure how serious they were. That's when they told me she was really upset and sad from it. I talked to the other girl she was with at the time and I told her I was just trying to be funny and I would never say that to be mean. I really try to be a nice person. I didn't really have a chance to apologize to the offended girl, but her friend said I should just probably never bring it up because she can be hostile. 
Later I figure out that the girl thinks it was my twin brother who is the douchebag and was telling his girlfriend that "her boyfriend was a douchebag."
<bot>: I accidentally called a girl fat while trying to make a joke and now I'm a douchebag. The girl thinks it was my twin brother. I feel bad.