Soleil,
I don't spot like that every month, but I have a few times since ttc. Then when my period does finally come it's sooo heavy, like everything that was saved up during those 4 days of spotting comes at once in a giant gush. My progesterone also was tested and seems to be normal. Maybe it's just stress? Do you exercise a lot? I'm not saying that's what's causing it, but I was wondering if maybe exercising too much was causing my spotting. It seems to be better when I take it easier. But I can't prove that scientifically.
I know you've been trying more than a year - have you ever been checked out for fibroids or anything like that? That's the latest thing that has me worried with my weird periods. It's so hard to know where the line is between paying diligent attention to our bodies and becoming a hypochondriac!
Hey, piccolo! I don't exercise enough!

I started yoga in August last year and went once a week, but it's been a month since my last visit. Argh. Will get back into it this week. So, if anything, lack of exercise might be a problem for me! As for the fibroids, I haven't thought about it. My periods are never heavy. The first day (after a few days of spotting) is medium and then it just gets lighter and lighter. It does linger for a while though. Between the onset of spotting and it finishing = about a week and a half!
Don't worry too much about the fibroids. I knew a girl who had them; she still got pregnant and now has a 7 month old boy.