Odor smell during period

Now third month that this happens. I had unprotected sex in October. Following that my period has been off. On time but now the smell is not normal. Very strong smell of like fish I don’t even know how to describe it. The first two days of the period is super light brownish with the smell. I used to be really heavy starting day one now it happens like day 3. I’m worried about the smell most importantly. It’s not like I don’t shower and stuff. But the smell has never happened to me before.