(Concern) Re-orthodontic period and side effects

About 20 years ago, when I was a student, I had braces because of crooked teeth, overbite, and front teeth that were really problematic. But I didn't realize it when I became an adult, until one day I went for a check-up at a local dental clinic and found out. They said I had a malocclusion where only one point of my back molars fit together, and the rest didn't match. When I went to an orthodontic specialist, they said I needed treatment, but now I feel anxious about redoing it. Since I'm an adult, my teeth don't move easily anymore, and trying to move them artificially twice might take even longer and could cause more side effects, which worries me a lot. I know I should do it, but I'm so anxious that I might even develop insomnia...