I'm 9 months postpartum, I had my first period on Dec 16 2022 and second was on match 12 2023 but that lasted only 2 days. so I took 3 pregnancy tests at home 1. Last month, that was negative 2. At the beginning of this month, that too was negative 3. Today and that was positive then I went to the laboratory and took a urine pregnancy test and that was negative, they said that it was so negative and there was no chance of pregnancy. Can anyone please tell me why this happened?