Does this look like hair loss/thinning to be worried about?

I've recently been thinking about going to get blood work done.. My hair has always been super thick, sometimes to the point of being hard to manage. But the past 2 months or more its become really noticeable that the new hair growing in is very thin, kind of transparent, and I can see my scalp. If I part it into sections it's a wider part than it used to be. I never used to be able to see that much of my scalp.. And I don't notice clumps of hair falling out or anything, it's just growing thinner, or maybe it comes out when I shower? I don't know. Pics below. I'm 20 and female by the way.



http://s120.photobucket.com/albums/o165/



http://s120.photobucket.com/albums/o165/Does this look like hair loss/thinning to be worried about?
you should go to the doctor, just to be safe.

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