Problems with my Corsa

I have a 53 plate Vauxhall Corsa, theirs a few problems with it but don’t know how they have come about, the engine is very noisy its a petrol engine and it sounds like a diesel! When the engine gets warm the oil light comes on but theirs plenty of oil in the there. I have just been on the motorway and smoke started to pure from the exhaust every time I pressed the accelerator and the car became very sluggish and didn’t respond well when I did press it, also when I kept my foot on the accelerator the engine started making a funny ratter ling sound,

Does anyone know what is causing this and is it going to cost loads to get fixed?

Any help would be appreciated.

Thanks,