confused

So, for me, AF is never late, she’s always right on time to visit. She was supposed to be here on the 4th, and today’s the 6th and she’s still a no show. My boyfriend and I have unprotected sex. It had never occurred to me, if i was going to conceive or not, though i’ve wanted to, just later on down the line if i had a bit of control over it, simply because he’s 16, soon to be 17, and i’m 18. We both want to have a family though. I took a pregnancy test yesterday and it came back negative, but i still have a feeling i might have did it wrong, being it was the first test i’ve ever taken. Help please? 😭 (we had unprotected sex a day before i ovulated, and also 6 days ago as well, if this helps?)