I had my 4th child 5months ago, then had my tubes tied about 2months ago. After my tying y tubes, I had a period for a month 1/2. then I stopped now, I have been having one for almost 3 weeks now. Is that normal? I never bled that long before even after all my other pregnancies. The most I have bled for was 1 1/2 weeks after my pregnancies, and about 2-3 days for a normal period.. should I call a doctor??

Yes.

I Think this is unusual bleeding. Even for postpartum. It could be nothing, but are you willing to take that chance?