this is a piss poor explanation of whats going on.
does you a/c blow cold?
do you mean the a/c compressor shuts off and on? if so your low on refrigerant. and it gets filled from under the hood.
if your brake pedal is hard, and you need to push harder good chance you cooked your pads.
a bad master cylinder would give you mush for pedal feel and even drop to the floor aka no brakes.
the vac booster i think would make your pedal hard, like the car was off. but i think you would hear it leaking. a hiss at least maybe after you turn the car off, coming from the booster area. also check the vac line to the booster and the rubber seal the line goes into the booster.
if your cam was causing it you would have felt this problem right after you did the cam, so dont think that has anything to do with any of your problems.