Sofa?

My sofa and loveseat are only a year old and they are alreasy ruined we live on our furniture it's the only family area we have and we made the mistaek of getting overstuffed loose cushions. Now are sofa and loveseat are lumpy and sagging to the floor....how can we fix this I even think one of the boards or something is broken/ I am willing to do whatever it takes we cant buy a new one anytime soon, and we are good at DIY. recushin? slipcover? What?