I'm another who can sympathise.
Lottie is just perfection at times, playing happily or snuggling up on a lap.
The next minute she is all teeth, biting fingers, arms, toes...you name it.
I went through exactly the same thing with our lab, which was years ago but I remember it so clearly. My kids were young at the time and quite scared of the biting. This time is much better in that respect, we are all working to stop the biting.
We are also struggling with sleepless nights and the house training is hit and miss. She goes in the garden lots of the time, then another time will come in after a long play session and squat on the carpet.
I know it all gets better, so stick with it.
In a little while we will all have loveable, housetrained, obedient pups who don't bite.....until then we can all moan together