You are to be congratulated for making such positive lifestyle changes. Titrating off unnecessary meds, exercise and veganism are not easy choices! I managed the first two but never got beyond ovo-lacto-vegitarianism, cappuccinos being my drug of choice! As to "How long will this last.....?" the more you worry about it the longer it will probably last!

I found that mindfullness taught me to "accept" my problem with sleep deprivation and that mindfull meditation helped me to relax enough to sleep, for 5-6 hours a night, which is almost enough for me. I am not an MD but I would suggest that melatonin ... (which is natural yes....but is that relevant? Poison ivy is also natural!) ... can cause problems if used long term.

Best wishes!