Vaginal pain - thoughts?

I'm 31 weeks today and for the past week or so I've had sharp pain every once in awhile - feels like its up in my vagina. It almost feels like sharp uti pains so my ob tested me Wednesday for a uti but I haven't heard back yet so I'm assuming it's negative (and no other uti symptoms). Sometimes I feel it when I'm walking my dog, doing laundry etc., but it feels better now that I'm sitting.

It's not round ligament pain or achy pelvic pain - I have both of those sometimes too. This is like a sharp stab in my vagina.. Thoughts?