I am 51 and used to have healthy skin, beautiful skin on my face, but now...?

I have been on hormone replacement therapy for about three years. My face is dry and flaky (not hideous looking), just tiny flakes. This shows up when I try to put on foundation, even after moisturizer. It depressing. Also, the colors of eye shadow I use to use look weird on me now. I have green eyes and brown hair - not much gray and I don't dye my hair, but I really am depressed about my skin's texture. The skin tone is sallow. It used to be rosy and pretty. I try to drink a gallon of water each day, as my doctor recommends, but that is awfully hard to do sometime. I put on makeup for the first time, in a long time, today, and the flakiness just made me so sad. I used to have a pretty face. I don't have many wrinkles, just really dry skin. Can anyone help? It is more for my self-esteem than anything. I see all these older, pretty ladies on television and they all still look so young and pretty. Wish I knew their secrets. Help. Any advice is appreciated. By the way, those foundations that say they are moisturizing don't seem to work on my face.