Awkward situation

So this past summer I went on a backpacking trip with a couple of guys. Its totally normal for me cause I struggle to get along with other girls. Well I made a really great friend and we go to the same college and sometimes grab coffee and do homework together. He told me out of the blue the other day her had a girl friend. I was really chill about it but when he decided for all three of us to have dinner together I was a bit more than nervous. Anyway, this girl glared at me the whole time, and was really clingy. I excused myself early and went back to my apartment. I dont know how to feel rn. I'm a mix of jealous (to be perfectly honest I did kinda like him) and scared that I'm gonna lose my one of my best friends. What should I do?