Suggest Treatment For Irregular Periods And Bad Cramping

hi im a 21 yr old female and normally have irregular periods but normally one a month still but normally only last 2 to 3 days, but for the last 4 months i have been having blood when i wipe myself and it colud last for 1 day, maybe 2 days maybe even a week then 2 days later it happens again, whilst this is happening i am having very bad crampin, tightening pains right down below by my ovaries what is this?