Large Clots during period after having son, and my during my journey to lose 40lbs;

My cycle is so embarrassing this month I went through 5 pairs of shorts since yesterday due to bleeding out of pads because of big blood clots. I have a 3 month old baby, and since I stopped breastfeeding I'm not getting as small as I was right after having him. I actually gained back a significant amount of weight. I'm trying to lose about 40 lbs to be ideal. I had no tampons on hand this morning so I grabbed a few pads and went to a graduation. I began to bleed through the first pad within the first hour, mind you I'm use to something much lighter. I was so nervous I shoved tissue behind the pad in my pants to stop the leak. Another hour goes by and I feel really wet down there so I rushed to the restroom, the tissue and pad were soaked and there was a little stain on my pants. I used the other pad and more tissue and got home 2 hrs later and once again the pad, tissue and toilet looked like it was attacked by Jaws, (the shark)and when I push little blood clotta come out - Is this clotting more to do with my body changing after having him, the Weightloss or both? :$