What Causes Spotting With Fever And Vaginal Itching After Periods?

Hi. I had my period at the beginning of this month on-time and regular. 4 days after my period I had to take the Plan B Pill. 5 days later I got my period again, and it was a regular period. Again. Today, I am spotting again and I have a fever and slight vaginal itching. Can you help?