Infected vagina ??

So I woke up this morning to take a piss and as soon as I had finished my vagina stung and i felt like I still needed to pee but nothing was left 
I went back to bed and my vagina was still stinging ? 
I had protected sex a couple of days ago but when I stayed over my friends house a guy fingered me when I was sleeping so I don't know what it could be from !