I am pretty sure I know what happened.
You pulled into your site, lowered the tongue jack (when I say lowered, I mean you lowered the jack wheel/base) to raise the tongue off the ball of your tow vehicle. Your kids then cranked the stabilizers down nice and snug (and maybe not even too much). You then realized the trailer was not level--too low in the rear. So to fix this, you correctly went to the front and cranked the tongue jack up (the jack wheel/base) to lower the front and therefore raise the back to level the trailer. This is all good, except you can't level a trailer using the tongue jack when any of the stabilizers are down. In your case, while trying to lower the front, you raised the tongue jack (jack wheel/base) until the jack wheel/base were off the ground and the entire weight of the front of the trailer was supported by your stabilizers. This will definitely cause the door (and other things) to have issues.
The good thing is, we often only do things like this once!
Best of luck during the rest of your trip!