What Causes Stoppage In Menstruation?

hi im 20 fm,i had sex with my bf in periods time tht is 1st day,his sprm nt insertd into my vagina bt my periods are stopd,last 2 days periods vl cme again,legs pain,head ache also coming and the problem is when i will go to urine there coming drop of blood and some particles...please kindly tell me the solution