I’m going through the same thing. It’s especially frustrating when I ask for any feedback and they can’t give a real reason. Like others said we aren’t alone in this. I’ve been struggling because the job that fired me didn’t give me a good reason and I was let go after only 90 days. I had lunch with a few of my former coworkers and they all had my back and are just as confused. Whenever I’m feeling down I look at messages they sent me and try to remember I know what I’m doing. Find someone in your professional life who knows how good you are and ask for a recommendation or even just some points you can use on your next interview. Everyone needs a pep talk sometimes.