Second opinion

I had my period for five days, November 18-23, my period is usually irregular but has been regular for a few months now. About two weeks before me and my boyfriend were feeling around. He made me finish, then I made him finish. He finished on his stomach, but five minutes later realized I had some stuff on the inside of my leg. He hurried and tried wiping it off saying it can’t get inside of me. We didn’t have sex at all. If we did, we would’ve had protection

I’m 16, and have small boobs. Recently I’ve noticed they’re growing. I’ve tried seeing if my nipples have changed or looked different, they don’t. Today I started having cramps, but that usually doesn’t happen unless it’s a week or so before my period. I’m kind of stressing, and don’t believe I’m pregnant, but I just need a second opinion. What do you guys think? I know this is stupid, and I’m young I know.