I know there's some cars which are known for problems like this, for example Punto's had/have a problem with the handbrake levers which operate the rear drums bending, but in most cases all that ever caused was the constant need to adjust the handbrake to compensate until the troublesome items were replaced.
It is certainly possible that if your brakes have overheated (especially drum brakes, they are at more risk of overheating when compared to disc brakes) they cool down and result in problems like this.
I know it's a little late to say it, but always leave your car in gear. I personally do this automatically now, but that's because I've always driven around in old wrecks
. But even in my Fiesta which is the newest and tidiest car I've ever owned personally, I still do it automatically and it's a habit I don't think I'll ever get out of, of course it's not a bad thing.