My Brakes Hate Me, Advice?

So we have a family friend that is a mechanic that we go to for jobs we don't have the time or tools to do. Anyway, my brakes keep deciding to crap out on me exactly 3 days before I go to my mechanic. The last time it was that the rear drums weren't auto-adjusting and that fixed the issue. This time I have no brake pedal at all. I slam it to the floor and it barely slows down, almost ran two red lights on my way to work this morning (my fox is my DD). The last time I still had pedal and was able to slow down properly.

I checked my brake fluid and it seems to be low. Where would be common leak areas and why are my rear drums not auto adjusting? When I first got my fox I rebuilt both drums with new springs and hardware.

Thanks in advanced for any advice

I didn't replace the brake cylinders or the adjusters because they looked to be in good condition and I was on a very low budget at that time. The pads for both the front and rear are only 6 months old so I wouldn't think they would need replaced already. I only drive on the road/interstate and don't abuse my brakes, never locked my tires up with them either.

I still have that gush sound. In the engine bay I found the A/C Vacuum connection was dry rotted off so I just need to find some rubber tubing and a clamp to fix that. It wouldn't have anything to do with the brakes would it?

I'll have him look more deeply into the problem then just the rear adjusters then.

Thanks