I had surg. in 2005 and yes, I went through the hair loss thing too. It is normal - even if you didn't have RNY surg. - surg. itself is a shock to the body. I think anestisia causes it too. And I had a lot of hair! My brother made a comment and then I stupidly went and cut it into a bobb. Keep up with your protein and vits. It will take a while for your body to adjust. There are also hair,skin,nail vits that you can take too. I never found that "special shampoo" worked very well either.
I know it freaked me out when I saw how much hair would come out while brushing it but it did come back. And, think of it this way, if you're really compliant with all the vits, protein, minerals,etc. that you should be getting your hair will show it. I even took pre-natal vits rather than the hair, skin, nail vits because I needed the iron. That worked great for me. (When I was in college I lived upstairs from these guys in a band. They all had long beautiful hair (like not a split end in site and to their waist) and they took pre-natal vits.
Just give yourself some time, your body needs to adjust. It will come back.
Deb