Diffuse thinning? or normal?

[BoSox]

I've posted pictures of my hair before, and i've been told that people don't see any signs of hair loss.

I have "fine" hair, and with my hair standing up on the top, I can see my scalp easy. Here are some pictures of my head with direct sunlight.

Now, you can't tell me this is normal :/


http://img153.imageshack.us/i/87034053.jpg/

http://img853.imageshack.us/i/ds2i.jpg/

http://img200.imageshack.us/i/40924054.jpg/

My hair does lay flat on the sides, so it appears darker.. but when I shaved my head last year, it still seemed darker.. So i'm pretty sure I have diffuse thinning :*(

Should I switch to Avodart instead of Propecia that I've been on for 4 yrs now?

I can't deal with this hair being so thin, if it were normal I'd be ok with it.. but if it's due to MPB... I want to fix it the best I can.