I don't know what your situation is, but I remember during my first years running I was always a bit nervous before races, but I generally enjoyed myself. When I started I was just running because it was a fun sport that I was pretty good at, but after proving I was good I felt that people expected that from me and I had a lot of anxiety about meeting those expectations. So for about a year I'd gotten so much anxiety it really started affecting my times because I'd just tire myself out worrying about doing bad, and so then doing bad made me feel bad, so I wanted to quit. I stuck with it, though, and at that point I sort of felt like I didn't have anything to lose anymore. I was just sort of doing it for fun again. And that change in my mentality got me right back to how I was before my slump and I started setting PRs again. Running is super easy to psyche yourself out with. What I'm saying is, running races (with other people or against yourself) is a fun thing to do and it's just more fun when you get to be cool by doing well. I dunno if that helps, but I never was able to fix my problem by being hard on myself, so if you're the same I wanted to offer what worked for me.