plz help

i have irregular periods but they started being regular i have one every month but my last cycle was july 26-29 and August came i didnt have a cycle i was worried cuz i been having them every month and then sept came and i was cramping and i knew it was coming on so i blood and i thought it was on and it was brown so i thought it was old blood and then it was pink and red but it was very light to the point i didnt have to wear a pad it lasted for about 3-4 days when i wiped it was there and only one time i pee and it was blood in the toilet and i had sharp pain in breast and was very tired but still no period and i took a pregnancy test oct 1 it was negative so what should i do