Can Someone Help Me? I Started My Very First Pack

Can someone help me? I started my very first pack of birth control pills (I take Junel 1.5/30) combination pill. I started the 13th of December. I missed a pill the first week on the 19th. On the 22nd, I took the pill about 3-4 hours late. Today on the 31st, I had unprotected sex. I'm so worried because it's my very first pack of birth control and I missed the 19th then took the pill late. How does that affect me? What are my chances of pregnancy?