I just noticed this a week ago. I dont have a clue why   :(.
I dont wear tight hairstyles or use chemicals or heat on my hair. I CO every third day and occasionaly use a sulfate-free shampoo on my scalp. I do use a BBB to smooth out the top but not on the length.

Here is a picture:
http://img.photobucket.com/albums/v384/AmethystRose/thinninghair.jpg

I am only imaging it? Please help!

Are you brushing or combing too much?  That can cause breakage.  Also, I find wearing my hair back too much can cause breakage too.  Take it easy and hopefully, it will get better.  

No, the only time I comb it, is to detangle before washing. And I only use a BBB to smooth out the top when I pull it back.

Do you know if it's breakage or if it's shedding from the root?  If it's breakage then I'm in agreement with kathy, just be extra careful with your hair and it should be fine.  If it's shedding from the root,  you should probably see a dermatologist.

Some thinning can be caused by clogged hair follicles.  Hair products building up on the scalp can cause this.

Thyroid problems can also cause loss of hair and thinning.  Only a doctor can determine if your thyroid is the issue.

Breakage, of course, is a whole other issue.  

I would get my thyroid checked out eventually, but right now I have no health insurance  :(. I doubt very much its breakage. I take very good care of my hair.

Another thing: I've been under a lot stress lately, could that be a factor?

Absolutly-stress can make your hair fall out.  If you can do some stress reducing techniques (yoga, meditation, hot bath, massage, etc.) and add a B-complex and a C with bioflavinoids it will help.

Good Luck!!!

Since it's thinning and not breakage, you could try womens rogaine.  It's available over the counter now so you don't need a prescription.  The generic version is only about 10.00 and I think it lasts a month.  On the side of the box, there are illustrations of the types of hair loss that it's most effective in treating.  Since you can't get to a doctor right away, if you feel it might work for you maybe it won't hurt to try it in the meantime.

You could also try Biotin.  My doctor recommened it to me to help with hair loss.

If it starts to get worse, I will definatly try the Rogaine. I have been taking biotin when I remember to, guess it isnt effective that way, LOL.  I'm terrible at remembering to take pills. Maybe I need to tie a string around my finger. Thanks for the advice everyone!  :)

You're welcome! I really hope it doesn't get worse, in the meantime try to relax and cut down on your stress.  Good Luck! :)