can you post the recipe?
even if the baking soda is not that old, I would try it with a new one...
your oven got broken and is too hot/to cold now. Check it with a oven thermometer
LiGruess cara ~~~ Life should NOT be a journey to the grave with the intention of arriving safely in a well preserved body, but rather to skid in sideways, chocolate in one hand, wine in the other, totally worn out and screaming "WOO HOO what a ride!"