I have done this several times and I urge you to remove the entire floor down to the subfloor, taking out the toilet, vanity, etc. You might try ceramic tile. It is not really that hard. You can use floor leveler/morter to level the subfloor and then lay cement board. The tiles go on top of that with morter mix. Any home center can show you how. The result is amazing and adds to the enjoyment/value of the bathroom.