Help!

My husband and I recently found out we were getting custody of my 3 year old nephew so we decided to push back having a baby of our own.. Well last night we had sex and normally we are careful but things happen. My concern is I noticed on here that I should have been ovulating when we did and I want to know if I have time to take a Plan B or is there a good chance I am already pregnant since I was ovulating. I just don’t know how fast it takes to get pregnant during ovulation.