What Causes A Missed Period With Negative Pregnancy Test?

hi doctor i got the period on may 25 now i missed the period on june 25 this is my 7th day of miss period on 7th day i taken urine test but it shown negative but i am feeling some symtoms like pain in the nipples and darkness one of the most thing i should say i taken pcos treatement by using krimson 35 after that i am geting my periods continously.please tell me i conceived or not