Sad, could it be my weight

Well, my AF came in full force today. These last two months have been emotional up & down. On Friday I have a light positive and the next day nothing and this morning my AF came in full force w/ good size clots (possible chemical?) I had the same things last month with the a very very light positive and the next day nothing.  I'm 29, 326 lbs , 5'7. I am also training to walk a half marathon in Nov.