Mouth ulcers and bleeding & senstive gums?!

I’m nine days DPO with negative tests so far (still reasonably early I know but 😩) and I suddenly have the most sensitive & painful gums when I brushed my teeth before bed this evening and then I noticed lots of ulcers that have appeared suddenly in my gums too. Does anyone else experience this before a period/after ovulation? I don’t think it’s an early pregnancy sign but it’s weird and sore and might be totally unrelated but I can’t help but wonder. 🤷🏻‍♀️ x x