Met a girl online, thought we had a connection, but now I’m confused.

I (24M) met this girl (23) online 3-4 months ago when I was going through a rough patch—dealing with a breakup and feeling lonely. Over time, we got close, and I started developing feelings for her. She seemed to reciprocate, at least over text. We met in person for the first time in Valentine’s week. Last week, she invited me to a club in Gachibowli, so I went. She brought her friend along. To give some context—she’s a regular at clubs and pubs on weekends. At the club, we ordered drinks, had some food, and chatted a bit. But then, she and her friend started openly checking out other guys right in front of me. I’ve been to clubs with other female friends before, but this felt different. It caught me off guard. She also seemed to know a lot of the guys there, probably other regulars. I won’t lie—I felt really bad about it. We kissed and hugged that night, but I couldn’t shake the feeling that something was off. Since then, I’ve been overthinking everything. Is this kind of behavior normal? Was I just reading too much into our connection? I tend to get attached quickly and struggle to move on, so this is hitting me harder than it probably should. Has anyone been in a similar situation? How do you stay mentally stable after something like this? Would really appreciate some outside perspectives.