TD5 Engine Temp Fault

Need some advice, my TD5 engine has developed a fault, out driving yesterday and all of a sudden my temp gauge went into the red the oil light came on and engine lost power, when i checked engine didnt appear hot and oil levels fine, left it to cool down then tried to start it and temp gauge went straight back up, oli light still on and wont start....what do i need to check?

that you actually have oil pressure and not just wiring fault