I'm looking for advice from people who have learned how to deal with having what you might call a 'fragile' mindset.

About me: I've had two long-running insecurities. One is my height (I'm about 5'6/5'7 I think) and the other is about my social skills. I'm often worried about coming across as weird, but I am starting to learn to express my authentic self. Aside from my height, I'm a physically attractive guy. My career is going well for my age (21, commercial mathematician) and I think there are a lot of things that make me unique.

On paper, I really shouldn't be struggling! Sometimes, I even have a really high self-esteem, and sometimes I feel great about myself.

I've been practicing night game for a while. My biggest problem is that the moment anything negative happens, it throws me off so much that the night becomes almost unsalvageable. This is usually because it activates a deep-rooted insecurity and I immediately feel embarrassed and worthless. Here's a great example of what I mean:

My most recent night out was with a friend. We met up with some girls while we were out, and my friend paired up with one of them. The rest of the girls found some random dudes... until it was just me and one girl left. She was being a total bitch. Boring. Not responding to me, closed off body language - the kind of girl to dance with her arms crossed; Even her friends were confused about how weird she was being. That is, until this huge (about 6'4) super muscly dude shows up. All of a sudden she's in a great mood. She ends up eating his fucking face off.

Now logically I understand that I'm not everyone's type. Logically I understand that it wasn't my fault - and also, anyone who acts like that is NOT my type anyway. Despite this, having that happen fucking shatters me. All of a sudden I feel like a child. All the guys look massive and way more alpha than me in an instant. Everyone who I was out with is now pairing up, and I'm left to fend for myself. I just go home, defeated.

This is how a lot of my nights go, because my friends find it super easy to hook up. I know that if I had a more robust mindset, I would be a lot more successful - because the truth is, I AM an attractive guy and I DO have potential. My first ever cold-approach (when I was 17) got me in a serious relationship for about 3 years with an extremely hot, high-value girl. Back then I felt invincible, but life has kicked me down recently (mostly because this girl fell out of love with me and let's just say I was replaced while we were still together) and I developed an unhealthy self-hatred.

I'm just trying to find ways to develop a more robust mindset. To understand that not every approach will be a win, to release the pressure and to just have fun with it and not let everything kick me down... Has anyone learned to deal with this before?