Post Partum Anxiety around other people

Does anyone else have a similar feeling? I just got home from doing a joint bday party with a friend of mine at her apartment for lots of our friends. She’s not married and doesn’t have kids, and I’m pretty sure most if not all of the people at the party do NOT have children (were late 20s- mid 30s). Most of the time at the party (my own party) I was pretty anxious thinking about my 7.5 month old daughter who was at home with her loving grandmother babysitting. I was thinking “These people (at the party) have no idea what it’s like to have a baby! They can just stay up till sunrise partying!” I felt weird and out of place and guilty for not having more fun after spending a good amount of money buying alcohol and food for the party. Most of the time I just wanted to be home alone with my baby, breastfeeding her while laying in bed. Does anyone else have this feeling of being very out of place around others? I’m a stay at home mom for now so a majority of my day it’s just me and baby at home. I cried on the way home because I felt like I was mourning my former skinnier, fun-er self, and thinking how I don’t even know who i am anymore. I still haven’t lost at least 15lbs and I’m tired and my whole body feels different. Does anyone else relate??