Wanna hide away but got FOMO

Ok.. so typically me and my two guy cousins ALWAYS do things together. But lately I've been down in the dumps almost depressed like with myself and haven't wanted to do anything more then play video games with them and that's rare for me rn. They went to play softball today (they asked me to go but I turned them down with a excuse) and my little cousin posted a video of them and well... I'm super upset bc they are having so much fun and I could be too but I didn't go. I'm having hella fomo, idk what to do