About Three Weeks Ago, My Boyfriend And I Decided To

About three weeks ago, my boyfriend and I decided to engage in sexual intercourse. We used a condom from the start and he also didn't ejaculate inside of me. My period is only a couple days late from the 17th and I will admit to stressing about it. I have irregular periods already, but with my anxiety kicking in, I cannot help but feel I could be. I haven't exhibited any signs of pregnancy either, not even the implantation. I just need help trying to figure it out! Thank you so much!