Hi Wendy
That's so typical, isn't it! He sleeps and you're the ones awake
Glad he seems to be settling so well.
I wonder if he was hearing noises that were unfamiliar (hoover, washing machine spinning??) and that's what was making him shake? Everything will be very new for him and it'll take him a little while to get used to all changes.
As for leaving him on his own in the pen for short times, has he got things to play with and chew in there with him? Also if you want him to spend time in there it's important never to take him out while he's kicking up as fuss - wait for a lull in the tantrum, even if it's only a 5 second lull
. If you let him out while he's barking and yelping he'll see it as his ticket out of there and will continue to do it
I'm sure there will be someone along soon with more suggestions
Enjoys the first full day with your new baby