You don't have to loose fluid to experience failure. In my case the fluid was getting past the cups in the master cylinder, so for months i did not loose a single drop of brake fluid. Then after having the same issues as you, one day poof, no brakes. >>>>>>>

Exactly what happened to me.

 

My ’93 would get a (red) brake light warning. I checked fluid OK, ended up the rear brake shoes where very warn. Replaced, no warning light now. My ABS is disconnected (connector) in the summer time. (I do get the yellow ABS warning light) I like the harder stopping power with them disconnected.