Almost 3 months delayed negative pt

Went to OB na and impossible daw na di pa madetect? But may nababasa po ako dito they reconfirmed after Trans V. :( 4 months after I gave birth last menstruation ko. Bfeeding din po ako pero first time ko ganito katagal mawalan. Any mommies who experienced the same? Nagkaron po ba kayo on the 3rd month?