tubal 13 wks pp no period.....

I had a tubal after my son, I'm 13 wks pp, still haven't had a period, I did test 2 weeks after the one time we had sex(8wkpp) before splitting up it was negative(I always know by two weeks with all 3 kids I get too sick by week 3). but I have horrible period cramping pain like doubling me over pain the last 3 days n no period still. how long did u take any of u guys to get a period bk. my baby was bf early on til his was 1.5 mo he started getting milk I was drying up due to all the stress I was under. need help....