Ibuprofen and period..

My doc put me on 800mg ibuprofen I take one at 6am w/ birth control pill. So by 3pm it had worn off I try to not take a second but my cramps are so bad my energy has depleted to zero and my flow went from very light to quite heavy. I've noticed when it wares off that these happen every time. I guess my question is. If I take another pill with the fact that it is slowing my period down will my period actually last longer because it is not fully cleansing my body? My doc had me on 3month BC to regulate my period so with this cycle I am due to get another one in about a week when I hit the sugar pills. I am also on day 5 I was light/light/med/med/heavy... Wtf!!