What Causes Intermenstrual Bleeding?

Hi,doctor i am 25yr. old female married Im not pregnant and i have been to doctor and he had chick up my vagina and if i pregnant or not by ultrasound and he said everything is Ok and he asked me to using fungi cream and after 3 days ago from my doctor visit is getting sticky light red blood from my vagina between my period occur for first time to me and i don't know what's that thinks a lot