I’m having trouble being comfortable when I go out with my friends

So I’ve always been the fun and out going friend but recently I just haven’t felt the same. During December 2020 – April 2021 we we’re back on lockdown in the U.K. and my mental & physical health were so bad, my vitamin d was so low I was so pale. Finally after April I decided to go to the gym and work on myself, it was going great until I started working from home. This made me so lazy to the point where I stopped going to the gym, I lost my job due to job cuts and then I became the person I didn’t want to be. I would literally lay in bed all day and only eat junk. I’ve missed my friends birthdays because I just wanted to stay at home and not go out. I feel terrible but I just don’t feel like my old self. Yesterday was the first time in months I saw my friends and I just felt so left out, I felt like I wasn’t included in some of the convos and I felt so out of place and uncomfortable. Today we went out to an event and I was there by myself for a while because my friends were late, I just felt so awkward. When my friends finally arrived I thought maybe that would be better but it wasn’t, there was so much going on so many people I panicked and went home without informing anyone, I doubt my friends have realised that I’ve gone because no one has messaged me to ask me where I am. I hate that I feel this way, I want to be able to go out and enjoy myself. From going out at least every week to now not leaving my house only for grocery shopping😭 I just hate this. Why do I feel like this?