I am in my mid-30s, and joined a startup back in Dec. 2020, and ended up getting fired in April 2021 after only a few months because of "poor performance" and a difference of opinion. I had serious anxiety about being let go and felt truly worthless, even though I never did poorly in previous positions. During that time I was in a very low place and anxious about how I was going to support my family ( have a 1 year old daughter), mortgage....etc without a job.  

I ended up finding another job a few months later at a larger but still very intense company. Now when I get critical feedback about my performance (in the first few months at this role),  I get really bad PTSD about being let go again. I have complete imposter syndrome now, my anxiety is at an all time high and feel just mentally unstable when it comes to my confidence and decision making. 

I can try to think critically about my situation and think about what I am doing well, how I was successful in previous roles, how I can motivate myself to be better now...etc but all of those things have little impact on my PTSD or anxiety no matter how much sense they make. I just get fixated on the negative and I dont know how to reduce my PTSD or anxiety in this situation.  I want to get better, I am willing to work hard to get better, but I just can't break free from the PTSD or anxiety.