My first AF PP was always heavey. Be sure to ask your doctor about it at your check though. Also when I got my IUD put in I was bleeding and my doctor said they pefer to do it then so they know your not pregnat. So no problem having AF while getting your IUD, but I guess its all up to the doctors. Good luck!
yes it is possible, alot of things can cause that, change in weather, food, excitment, depression, stress.
I've heard other women say that the first postpartum menstrual period is heaver than usual. Because I've breastfed and didn't have a period for months, I haven't really experienced this (my first period after having my first son came at 6 months postpartum once I'd weaned him and was normal in length and flow and, as for my littlest boy who is now nearly 5 months old, I have yet to have a period).
If you're concerned - or the flow remains heavy with clotting for much longer - I'd speak to your doctor just to reassure yourself.