Strong rotten odor

I’m 21 I’ve never been on birth control and I’ve only had one sexual partner ever. I’ve never really had issues down there but for about the last 4 or 5 months whenever I get my period it literally smells like death so bad that when I leave the bathroom after cleaning up the smell lingers I used to use menstrual disc but when it started to smell like this I stopped because I couldn’t get the smell of my finger when I had to change it now I use tampons. It takes almost a week after my period ends for the smell to go away and then everything’s back to normal until my next period. nothing hurts burns or itches. Any suggestions or opinions as to why it’s so bad?