I wear cotton underwear. I don't take oestrogen-containing birth control pills (I'm on a progestogen-only method, and I'm not having sex at the moment), I haven't changed my medications recently. I haven't taken any systemic antibiotics- I used a small amount of mupiprocin ointment on a mildly infected wound on my hip, but I can't imagine that would have major systemic effects. I don't have any relevant health conditions.
On my last STI screen my then-partner and I both tested negative, and I have no reason to believe he cheated on me or withheld information.
I have been really stressed about uni and work, which is the only thing I can think of that might be even remotely contributing.
Does anyone have any idea what might be going on?