Alrighty ... I’m 30 weeks pregnant and my last period was November 9,2017

I was with someone in October and left him and met someone new and my last period was November 9... I never received my period so I found out I was pregnant dec 24,2017

My current partner has doubts that it’s not his baby .

In October my period was late with my ex and I went to the hospital around oct 20-31 and they told me I wasn’t pregnant and there was no way to be pregnant.

Is it possible I’m pregnant from October? When my last period was Nov9?

Please help me out ...