Boyfriend ìs saying it not his baby.

I just found out I'm pregnant last week. I didn't tell my boyfriend that I'm pregnant the day I found out I'm pregnant because in December I had a chemical pregnancy and I wanted to be sure that my numbers were doubling and they are I got the call from the doctor today so I was very excited that everything is going great with the baby. So tonight I told him we are pregnant again and he is questioning me about how I ended up pregnant and than say how dose he know it's his because 3 weeks I ended up in the hospital because of my high blood pressure was very high so I want to the hospital and I had to stay over night so that they could watch my blood pressure and make sure it's going down and it did but I didn't sleep at home. He knew I was at the hospital because I ask him if he wants to take me too the hospital and he say how could he be any help there so I got upset and left and went by self. So now he's questioning me if that's his child because I wasn't home for one night. What should I do I'm so upset with him right now