Pregnant or not

OK guys help me out. So I just had a baby in July 06, 2023. My baby was supposed to be due on October 08, 2023. He is still in the NICU.

I’ve been frequently going to the bathroom for the past three weeks. Sometimes I am cramping from time to time my breasts are very sore more than usual. I’m breast pumping right now since my son is still in the NICU. Since I am breast pumping I had not had my period. I don’t know what’s going on. with my body. I’ve been taking the pregnancy test to see if I’m pregnant again, but they keep saying negative.