Hello, 26M here. I was invited to my friend’s engagement party yesterday, and while I was happy for my female friend, I couldn’t help but feel sad about the whole thing. The funny part is that I don’t even know where this feeling comes from. I’ve never been in love with her, nor am I jealous of the guy she’s marrying soon. I just got so mixed up by this bittersweet feeling, and it’s frustrating not knowing where it’s coming from. Can someone help?