Missing and unusual periods. Grateful.

My last proper periods were in January. Since then my cycle became unusual. Got two times periods in March but  both last only 2 days with very less bleeding. From March ending drop drop bleeding happened for approx 10 days. In end of April one day heavy bleeding with extreme pain. For two weeks bleeding happened for Wednesday only. I have noticed that bleeding becomes more on Wednesday as I keep fast, soon after eating I feel fine. My normal periods are for 3-4 days and they are usually late5-10 days every month. I am getting periods since I was 9 years old. I have less physical activity in my routine and normal eating habits. Last two years also my periods skipped for 2 months then it became fine of its own. This time condition is serious. Please suggest me something for betterment, I will be grateful.