Every time I flush my toilet, nearly all of the water goes down and the level is low. It slowly rises back up, but the flush doesn't seem normal to me. Also, my bathroom sink which is right next to it is very slow draining. I have read a couple things about clogged vent pipes on the roof, but I know nothing about that. Any suggestions?

Is there a gurgle from the lavatory when the toilet is flushed? Does the toilet bowl filled to normal as the tank fills? Any problems with the bathtub drain? Can you give us more information? Back to you, Tom