R.J.
I can ALWAYS smell everyone who uses pads. Always. Indoors is especially awful, but outdoors as well. And breathing through my mouth is no good. Then I can taste it. Shudder.
Most people can't.
Most people can't even smell really really bad smells until their nose is right next to it.
So for those of us who can smell appallingly well, don't worry about us. We're used to it. Heck, I use camphor under my nose when I'm in offices or close quarters with people (especially homes of people who leave sanitary products in the garbage instead of flushing or ziplocking). LOVE CAMPHOR! Trust me, those of us who can smell everyone take steps not to as much as possible.
For other people, they're undoubtedly clueless.
That said...
It's doctor time.
Most infections have very distinct, very bad smells. That would be my first guess... that you've got some kind of vaginosis going on. It's also not unusual for a piece of the uterine lining or a very very early lost pregnancy to not detach all the way and start decaying. Either way... it's going to smell foul.
Which means doctor time.