brakes giving me a headache!

You can isolate the master cylinder by clamping off the 3 brake hoses at the same time. You can use vise grips, but be sure to use a rag or similar in the jaws so you don't hurt the hoses.

If the brake pedal is high and firm while hoses are clamped off, the master is good. Bleed some more?? Brakes can be a pain sometimes....