Please can someone tell me, do i need a new exhaust if the car starts blowing, and loosing power?

I have a 06 reg astra sxi, it has 66 thousand miles on the clock, i was driving to work today, and suddenly the warning light flashed up about 3 times and the car lost power, i tried to accelerate and there was hardley any power at all, and the sound wasnt loud but it felt like a chugging feeling and a low blowing sound but only when i accelerate, should this be happening on a car of this age? im really worried please can someone help, if it is the exhaust could someone please tell me how much it would cost to replace the exhaust if it is the exhaust. any help would be very much apreciated. thank you.