I'd want a way to vent the shed when you aren't heating it - open doors I guess.
You got a lot of moisture coming out of the concrete, even out of the wood, and so forth. This time of year, even tho you didn't fill in your profile nor tell anyone where you live, most parts of the country are going threough sprting where there is a whole lot of shifts in humidity, air temp, and the temp of objects.
I went into my shed today, and part of the floor under the pickup, and _every_ tire in the place was damp. It was hot humid air blowing through the 1 inch crack under the doors, and passing over the very cold floor from winter, the moisture condensed out onto whatever it could.
For my new shed, it was damp & wet metal walls for most of the 1st year.
The 2nd year everything stablized & sorted out & the concrete got more fully cured, and it's been real good this spring, even tho it's been a cold wet one. I was a little worried that fisrt year for all the moisture in it!
Don't think I helped any, but the concrete should push out moisture for several months at least, and even if the wood was kiln dried it puts some out too, esp any piece of treated lumber.
My shed has a 6 inch screened gap on the top of both walls, plus sliding doors that have gaps, and mine still didn't vent out all that moisture the first year.
Vent it out more - fans just curculating air inside the building will not change much, the moisture won't go anywhere - I mean vented. You are capturing all the moisture inside the building with no where to go.
Be aware of the season & the air humidity and the air vs floor temp. Some days just will sweat, how it is.
Give it a year to get everything dried down.
--->Paul