Irregular Periods. Would you advice?

I've been having irregular, or rather almost never ending periods the last 4 years. I bleed for almost 2-3 continuous months and then have 3-4 clear dry months. Had been to a doctor in 2013 who wrote a complete list of tests and sonography.. The results were perfectly fine except for an indication of mild PCOS. My doctor tried to regulate my periods by putting me on Yamini LS for three months, a break of three months and a repeat of another three months. However, while my periods are regular during the course of the medicine, they get back to their erratic schedule once the course is over. This time has been the worst so far. My periods began on the 26th of January. The flow was heavy for the first 5 days and then very light and scanty for then next 20 - 25 days. It got heavy again sometime early March for a couple of days and then went back to just spotting until the 21st of April. It has been heavy ever since. What can I do? What course of treatment would you advice? I am overweight.