I think everybody's given you top notch advice so far - not much to add here - but thought I'd post a little trick I used to use before I moved to wearing years ago that might help you feel a little better immediately.

My own hairloss was much like yours at first, but not quite as diffuse. I drove down to the nearest drugstore and looked in the makeup section for a powdered eye shadow shade that matched my own hair (light brown), and using one of those triangle shaped makeup sponges, rubbed the powder down thru my hair onto my scalp to darken the white scalp down a little. Just a little of this trick went a long way to make it look like I had twice as much hair in the thinning areas.

I successfully used the powder as needed to camouflage my thinning areas on top until I eventually made the switch to a topper. It was cheap, easy and washed right out with each shampoo. For me it worked better and looked more realistic than some of those other fiber type concealers, and cost less too.

From looking at your pics I can tell your natural color is much like mine--not going to be easy to match. When you send in your order be sure to send a generous sample of hair taken from the top/front area of your growing hair to get a close match. Don't send in a samples taken from the back or from behind the ear, because the hair there is usually a shade or two darker than the hair on the top.