Irregular menstrual bleeding. Bleeding.

I used to have irregular menstrual cycle since 2 years. I used to get only 6 periods a year. I have tried exercising a lot because I'm a overweight but no change in weight. Since few months I'm having a problem like I got a very little bleeding on 14 October which lasted only 1 day and blood was very light. Again on November 14 I got a bleeding which lasted for 2 days but still period was very light. I normally get heavy bleeding when I get periods after months. Before this last proper period I got was on August 30. Then on December 5 I got a period. First day I got very little bleeding then from 2nd day I got a medium level bleeding till 4th day. On 5th day just got a spotting and stopped. But again after two days I got spotting again and on 7/8th day(don't know exactly) got a medium level bleeding and stopped. After spotting kept occurring and in between it again stopped for 2-3 days and again started. And since last 4-5 days I'm getting medium level bleeding.