Marina, I'm so sorry for this. I'm also going through a difficult time with mine just now. I do think it is the season. I hope it will pass after the new year.
You can protect your kids by being their safe place and letting them know that they are your priority. I'm telling you this, so I can tell it to myself as well. Kids like structure, order, safety, security. . . They like parents who parent and leave them out of the grown up stuff.
Keep staying calm, documenting, and reporting. The court will give great deference to the GAL.