The first few weeks I took nortriptyline at 10mg (similar to Ami) were the worst. I didn’t actually think it was doing anything for my symptoms (if anything, they were stronger) and my frame of mind was not good. I saw better results at considerably higher doses and over time. Nort and Ami are slow-acting; some people see results quickly but for many more, it would seem, it takes weeks and months to see meaningful progress.
If I may speculate, perhaps the anxiety is a function of expectations. These meds can be a long game; if you can, work toward acceptance that you’ll be able to assess progress in weeks/months, rather than days. See if it’s possible to feel calm and encouraged knowing that you are on a good path and going in the right direction.