Think my girlfriend cheated, need some advice(M18) (F18)

I really need some advice this is messing with my head i thought we were in love. So pretty much i’ve been with this girl for 10 months. we live together. we’ve been in a rough patch recently because of me fighting with her father. She tells me her childhood friend has contacted her and asked her to come and hangout at a hotel and smoke. i say okay that sounds good and i’ll go hangout with my own friend. fast forward a couple hours around 9 i call her and ask her what she’s up to. She says she’s just chilling and smoking with her friends. i ask her when she’s getting home and if she needs a ride, she says she’ll call me when she needs one. i fall asleep around 10 ish and wake up around 3 to no texts from her. i call her, and she says there’s no other dudes just her and her friends chilling in a room drinking. i ask her again if she needs a ride and she responds no. i can’t sleep at this point and it’s really unlike her to not come home. i trust her, watch a little bit of a move and fall asleep. i wake up around 9 am and she’s not next to me. i call her with no answer. i check her friends instagram stories and there walking downtown with a bunch of dudes at 3:45 am .i’m freaking out all day until around 5 pm she texts me and says she’s getting an uber home. she comes home looking really messed up, i ask her what happened last night sand she says exactly what i told you. i’ve caught her in a lie already saying she was with no dudes. she’s sleeping right now and i want another perspective because i’m bout to wake her up and tell her to leave. any advice is appreciated