I didn't cheat on my girlfriend and now I feel weird

Me (m23) and my coworker (f22) were at some company party a few days ago. It was few hours out of the town so I was driving and I didn't plan on drinking. She got pretty drunk and started flirting with me very agresivly (not in a bad way) and I pulled back from kissing her on multiple times. In the ride back she was reaching for my hand when I was changing gears, feeling up my arm and touching my leg a bit. It was really weird for me but I didn't do anything with her I just backed out of all of those things. I never thought about anything with her even tho she is smoking hot 10/10. I love my girlfriend, we have been together for a bit more than 4 years and even though we are currently in a bad period but I don't want do break up. I never told her what happened there because I know it would only make the situation worse. Tomorrow is my first day at work after that party and I'm gonna see my coworker. Idk what will happen and I'm having a lot of thoughts in my head. I feel bad that she even flirted with me and that I let her touch me multiple times, however I enjoyed the affection and I didn't want to do anything harsh to upset her. I am currently really fucked up in the head with the stuff that is going on in my life and only good thing is my gf. This is stupid post but I just have to get this of my chest.