Confused.

So, I just had a baby 5 months ago. I got on Nexplanon 4 months ago & have had periods. The past two months I haven’t gotten a period. I’ve dreamt of pregnancy, my friend has, & so has my mother. I took a test when I was late for my first period & it was negative. But I’m tired, nauseous to smells and foods. Basically everything when I was pregnant before but I know it’s almost impossible to get pregnant on Nexplanon. I’m just confused.