I think i know were you went wrong.
You say you used a mouse for sanding down!
Maybe you should of used something rougher to start with like a Rat LOL!!
You are certainly having a rough time with this hull.
In the past i have also had boats that did not want to be built so i know what you are going through.
The only advice i can offer at the moment is keep trying, just do a little bit at a time and when you are happy with that then do another little bit and so on and soon the worst bit will be over and you can start on the best bits.
Remember if i can help just shout.