How To Regulate Periods?

Hi. I am having so much problem with me period. Sometimes I don t get it at al, and this is the 2nd time since November that I ve been having it for 3 weeks in a row. Some days heavier , other days basically nothing . And then I have huge blood clots coming out it is so scary . I went for pelvic ultrasound and blood test as well in January, my doctors said I have a collapsing cyst but that shouldn t cause these symptoms. What s going on and what should I do? My doctor said take birth control pills which I don t want and I don t think that s a solution. I asked her to refer me to a gynaecologist but they won t see me right away have to make an appointment. Should I go to ER? I m so fed up . Thanks for you help in advance . Szabina