What is it?...Occasional Throbbing pain?

This is like a throbbing ache that's really low I honestly think it's in my vagina... I've had it three times now and it lasts around 10 minutes. I always drink more water when it happens so I dont know if it's related to that but does anyone know what it is or has experienced it? I dont feel I can describe it well enough to talk to the doctor about it with them going "yeah just drink more water and let us know if it gets worse"... I'm 14w5d any ideas?