Period & Weight Loss

I've lost 70 lbs in the past 9 months.

(I think I may have asked this question here before but I can't find the posting so I'm sorry if this is a repeat)

My periods are lasting longer, heavier, and I'm now getting cramps, (sorry TMI) diarrhea before AND after my period ends.

Beforehand I can handle but is it normal for this to happen afterwards?

Sorry, I know it's probably a dumb question but going from not ever experiencing PMS and 3 day periods to full on PMS and 5 day PLUS cramping,headaches, and staying near a toilet 24-48 after my periods is driving me nuts.

Thanks for any advice.