I installed the toilet in my bathroom on Wednesday and have had no problems at all, but last night on Thursday the toilet wouldn't flush. The water level would just rise. I tried using a plunger but that had no effect, other than hearing water near the sink move around. I left it overnight and the water level in the toilet went down to a minimum, so it is slowly draining, but not flushing. When I use the sink, the water level in the toilet rises and the water bubbles (obviously the water is going back up the pipe to the toilet or something). Do I have a clog in the pipe that is stopping 100% water flow or something? Let me know what you think. Thanks.