Weight Gain??

Hello ladies, So I just got my period today and I notice my flow is a lot less then usual Im pretty much just spotting. The same thing happened last month, I was worried maybe I was pregnant. I get very bad cramps back pains and I PMS like crazy that hasnt changed. My question is, I have been suffering from really bad depression and have gained a very large amount of weight so far this year. Could all the weght gain be affecting my period??  Not only am I spotting but its really light in color as well. Thanks to everyone in advance.