Vibrations/flutters in the pelvic area (mons pubis)

I had those vibrations/flutter for like 2 months, I started taking pills for UTI and I still had them for a few days before they disappeared for a month and returned yesterday.

They come and go throughout the day. The vibrations are short, very quick. No pain at all. No cramps. It can happen whenever day of the cycle. In the center of the mons pubis.

Not pregnant. I'm 19. Virgin.

I drink 2.5 liters of water everyday. Eat healthy. Do aerobics frequently.

I've never had this before.

So I don't know what this is or if it is a sign of something serious.

I've read a lot here and I don't find anything that explains why this happens or what should I do to stop it.