Ay mama, kahit may protection at withdrawal kaya pa rin may possibility lalo na kung breastfeeding ka lang, kasi hindi 100% guaranteed ang contraception, kailangan mo talaga mag-take ng pregnancy test para sure, lalo na may spotting ka and delayed period mo na. I'd really suggest checking with your OB agad para malaman mo kung ano talaga nangyari, baka stress lang from adjusting postpartum o baka may iba pang reason, pero peace of mind mo importante kaya talagang mag-consult ka na!