Scared I'm pregnant

Okay I've recently lost my viginity, we have had sex a fair few times and each time with a condom! The first 2 or 3 times he finished inside me (with the condom) and it wasn't leaking when he took it out. The other times I made him pull out because I was scared of getting pregnant. And the past 2 days I've been feeling sick and at night feeling like I wanna throw up. The first time I had sex was about 3 weeks ago. The last time was about a week ago.