First, it's OK to not cook. If you are getting by alright without cooking, there's nothing wrong with that.
Second, I respect you coming here and admitting your fear. Ironically it takes a lot of bravery to do that!
Third, irrational fears and anxieties are a normal part of the human experience. Everybody has them, so though it can feel like you're being stupid, you're really just being human (though some might say that's two ways of saying the same thing).
Fourth, I'm not a therapist or medical professional but the treatment for phobias I am aware of are CBT (cognitive behavioral therapy), ACT (acceptance and commitment therapy), and exposure therapy. You can find CBT and ACT workbooks that might be helpful. As for exposure therapy, I think it's best to work with a professional doing that. Exposure therapy is not just taking the plunge, there's a process to it. Of course, if you can afford it, talking to a mental health professional is always best.
Good luck!
I conditioned my statement with “if you are getting by alright”. If nutritional needs aren't being met that's not getting by alright. Though I can see how someone might interpret that differently, but that was my intent.