car last night and suddenly I lost power?

I was driving my car last night and suddenly I lost power, like when you run out of gas. I had about an eighth of a tank, but I added gas and still had the same problem. It takes forever to get the speed up to 25 mph. Even though I can hear/feel the transmission shifting, I just don't get any power. When I am sitting still, the car will chug and die unless I put it in neutral and keep light pressure on the gas. (I could probably do this in drive, just feels safer to do it in neutral.) Also, at the same time, suddenly my brakes got hard. They still stop the car, but instead of the nice easy feeling I get when I put my foot on the pedal, it's firm, almost stiff. It does stop the car tho.