Could I be pregnant? Update

I just had a baby in January & around March 18th I finally stopped bleeding for a day or 2 maybe & then started bleeding again so I'm not sure if it was my period starting but I counted it as a period & we had sex in my possible fertile window going off that as a period if it was I would technically be late bc I haven't started again since. I've been cramping in my right pelvic area today & when went to the bathroom this morning I felt nauseous & almost threw up....what do you guys think..could I be ?

Update I took a pregnancy test & it came back negative but was ones from Amazon so idk.