Can pms cause fatigue? and if so, how severe can that fatigue be? can it be like pregnancy fatigue, where you can actually fall asleep in the middle of the day from it?

There are varied symptoms of PMS&fatigue or even depression are some. If you're predisposed to retain fluid days before your period it can produce fatigue because of additional sodium& fluid in your body& swelling of the brain. Sleep disturbance may be part of the problem in some cases. I found that prescribing a mild diuretic a week prior to the period in these women often prevented PMS symptoms