Last night my BMW x5 overheated while driving and the coolant low light came on, i added coolant and it still is overheating. It is fine while idleing. Now today i was trying to look at it better and started the engine, it was fine. Then later went back to give it a testdrive and now it wont start. it acts like it wants to but nothing, and when i give it gas the pedal acts weak. does anyone know whats happened?

Probably toasted the engine. That can't be cheap.