brakes failed at a red light. at first it was just a regular stop but the peddle just went to the floor with no pressure. and now there is a burning smell from inside my rear tires (drum brakes). my car has 137k miles on it. the e-brake light has been lit up on my dash for weeks.

the brakes seem to be operating fine now, but i am afraid for this to happen again. should i replace the rear brakes?
any suggestions or advice please?

 

car was low on brake fluid. i topped off. i may have a leak. i dont know.

but the burning smell.. could this be caused by low fluid?