So sorry to hear you have had such a rough time of it, and sorry to hear about your MC. I also had one at 11 weeks and it took some time for my body to get back to 'normal'.
AMH is generally reliable and tends to trend downwards with age but it is by no means the whole story, and as many people will attest, quality of eggs is just as important as quantity.
AMH, together with FSH and antral follicle count gives the clinic the best idea what protocol to put you on and how you might best respond to which particular drugs.
Whilst you may not be able to reverse AMH decline, I do believe you can hold it off and also get your remaining eggs healthier with lowering your stress, better sleep, exercise, lifestyle, diet and supplementation.
Highly recommended is the book 'it starts with the egg'.
Sounds like you've made some big changes already and I'm doing the same as you in terms of removing work stress. Three weeks to go for me now before I go on a sabbatical from my ridiculously stressful globetrotting job. I hope it makes a difference.
Good luck with your next steps x