Mommy, ang stress mo talaga understandable especially with your complicated pregnancy history, pero kailangan mo talaga makonsulta with your OB asap, delayed period after childbirth can be so many things (hormones, breastfeeding, stress lang), at need mo ng professional checkup para ma-ease your mind, lalo na may history ka ng bleeding. Two negative tests is reassuring but your doctor can do blood work or ultrasound to be 100% sure, and pwede rin niya i-discuss with you kung anong contraception ang safest para sa iyo given your situation, kasi withdrawal is really not reliable especially if you don't want to risk another pregnancy so soon after a complicated one.