Clear water discharge during period.

Okay, I’m a bit embarrassed about this because I feel as if nobody has had this issue before except me. During my period I get this clear watery discharge that has a slight ammonia smell to it. It always soaks through to my underwear it’s as if it bypasses the tampon completely, it’s the most puzzling thing I’ve ever experienced. I just recently got a Pap smear and a full STD panel done as well as a urinalysis and everything returned normal besides the extra protein in my urine (which was discussed separately) and there’s no way I’m pregnant, is there anyone out there that’s experiencing this or anything similar! I’m upsetting not being able to find anything about this!