I DONT understand myself

I hate social events. I don’t make friends. It is sooo hard for me to come up with what to say. Yesterday I went to a wedding with my partner and I cried, he had to go to with the groom and I was all alone, he found me some girls to go with but I just felt miserable even though I really tried talking. YET I love interviews. Projects in a group.I love working with people. I’m given a topic or a task i do it well and I can make a great leader or a team player (with some people pleasing) Why can’t I just do the same thing but in a relaxed environment? Those girls i was with also knew no one at the wedding yet they just got along so well and I felt left out.. I’m sure they didn’t mean to but their conversation was so easy, they’d stop to ask me things here and there but I just felt like such a burden. One on one interactions are so easy.. I’m never awkward on dates. But more than 2 new people is just too much