The other day I was in a situation that required me to slam on my brakes from going about 40mph. After that my brake light came on (as if I hit the E brake) and it seems as though I have lost my power braking. I am still able to stop the car, it just takes more pressure and "throw" on the pedal than normally. I haven't checked the fluid yet, but I was wondering if anyone had any suggestions on what to look for. Thanks.

Look for leaks. In the rear you may have to pull the drum to find evidence or you may see the drip down the inside of the tire if you pump the brakes enough while sitting still.

check the break lines for a pin whole or leaks. you will see a wet spot.
Next check around the master cylinder for leaks.
if that all falls its either a internal master cylinder problem, or a rear wheel cylinder leaking.

I'd check that fluid damn quick. If the light came on, you're probably REALLY low, and if you DO have a leak, you won't have brakes soon. And if you pump air into the MC bore, you'll have to remove it and bench bleed it. Hydraulic systems don't work too well with air in them.

Sounds like you blew some seal. Check the insides of all 4 wheels for brake fluid.

if the pedal is hard, thats not a fluid leak.

thats a booster problem. fluid leak would cause the pedal to go to the floor, easier.

maybe check the vac line from the uim to the power booster

yeah, but that wouldn't cause the brake warning light to turn on

The stopping power of the car hasn't changed since it did when it first happened, if that means anything. Thank you for all the help thus far.

Whatr did you mean by "more throw on the pedal"? I assumed you meant it is traveling farther than normal; an indication of a leak.

yes, please clarify. bc i interpreted it as more force to get the pedal down.

Sorry for the confusion. The pedal travels further. Now it actually travels to the floor, and it is harder to stop the car than before. I didn't notice any fluid leaks, and upon first try I was unable to get the cap off the fluid reservoir. I will try again today.