Period probs

So I'm on my period right now but it's kinda weird. It's been regular for yearrrss now but this one is different. When I first started it was very light and not that red, and it was barely there. And so I put in a tampon expecting it to get heavier but it hasn't so much that my tampons are being barely used. I had to put on a pad last night cause the flow was so weak. It's never been like this so idk what's going on. Any ideas? (P.s- no chance of pregnancy cause I'm a virgin)