No way to know how your body will respond. I think though that it won't go back to a previous time, will be in 28+ days (if your stress or whatever is less); it has to do its thing and cannot do it "faster" (to be ready by your old date), only slower/longer.

I do not remember how old you are but if in your mid- to late-40's could be menopause messing with you. That can take 3-4 years and your period will almost never be predictable.