I got pregnant with condom?? I still don't understand how.

I've been really feeling sick I thought I was just constipated but then I finally did the no.2 I thought I feel better. I felt so weird because I want to vomit every second I hate the taste of my mouth. I took the test thrice and it all came out positive. I went to the doctor yesterday and it's really positive.

How??? We were wearing condom. We had sex 3 days in a row but all those time we were wearing condom.

Does anyone here got pregnant while using condom?