Hello, I ve 13 days out from my next period. I started taking amoxicillian due to having strep & the flu. After my first day of taking that, the next day I became very crampy. The following day I was still having crampy or lower pelvic/abdominal pain with when I used the restroom blood on the toliet paper. I m going on my second day now of the blood every couple times I go, not heavy, but still worried about it. Also, using restroom frequently. What could this be, should I be worried or is it a possible UTI.