Omg im so confused

I am trying to concieve my second child, with a different person. My period acts crazy. I've gained 70 lbs since my two year marriage started. I have tried everything even pops birth control to regulate it. Last month I had a period on the 25th very light. And then on the 5th another heavier than I've ever had it. Well it's the 6 the and no period. Took a test and not pregnant. I mean what is the deal????