am I pregnant??

Okay, so I got on the pill around 2 months ago, and I had sex for the first time around a month ago. We didn't use a condom but he said he pulled out. 2 days after we had sex I started spotting for 3 days. My period was supposed to be here the 3rd of January it's 10 days late. Could I be pregnant or is it just my body reacting to the birth control?