IM SCARED CAN I BE PREGNANT

First off I just want to say please don’t judge. I’m 16 and my boyfriend and I have been dating just shy of a year and we finally had sex. I always told myself not to do it without protection but I was wrong. We weren’t expecting to be home alone and well you can see where this is going. He didn’t use a condom and it was both of our first times so I was a little nervous and ended up making him stop before he even finished. It was fun but now I’m overthinking if I could be pregnant or not. It was day 18 of my cycle and <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">eve</a> said there was 3% chance of pregnancy that day. I know it’s not 100% accurate but anyways. I’m not on any form of birth control we didn’t use a condom and he didn’t finish I’m so worried because I’m known to overthink things. It’s stupid to even ask this but could I be pregnant? I’m taking a test Thursday should I get plan b?