Help!

Okay so, I'm a little bit worried. Over christmas, I had to miss a week of taking my pill right after my period, because I didn't have the money yet to go get a new pack. So the next week I started a new pack and the second week my bf and I had unprotected sex. He pulled out for most of it but he thinks maybe like 10% of it was in me. I've been on the pill for 8 months now, and this is really my only slip up. Should i be worried? Or am I just overthinking?