Self sabotage spiral

I do not know. Apparently, I struggle a lot with how I see myself, and the smallest things can send me into a huge spiral. There has also been a lot on my mind lately. I see old friends, and they all seem to be in different places in life. They are pregnant, engaged, or have stable careers, and then there is me, still struggling and not even wanting children, yet somehow feeling like I am falling behind.
It is hard not to feel like everyone else has their life together while I am still trying to figure mine out. I know that is probably not the full picture, but it is difficult not to compare myself. Sometimes I look in the mirror, and the smallest thing will trigger me. I guess it is not really random, though, because it almost always comes back to how I feel about my appearance and my worth.
Part of me keeps wondering how people stop comparing themselves to others. How do you stop spiraling? How do you stop self sabotaging when it feels so automatic? I wish I knew how to look at myself with the same kindness and understanding that I give to everyone else. I just look at myself sometimes and think what a fucking joke. I try and be strong but I feel sometimes it’s one thing after another and it’s so fucking defeating and I just wish I could change who I am and how I look and how I feel and then I’ll feel ya know what I need to stop and I can’t find the middle ground