I totally understand where you're coming from.  I spent the weekend from hell down in Chch in January last year with DHs family, I was so emotionally high strung by Sunday I cried at the airport when we were heading home. 

Michaela's uncles sound similar to your dad.  They speak aggressively to each other, they're just playing about but Michaela didn't understand that and within a day of being around them all it took was for one of them to look at her and she burst out crying and clung to me.  That coupled wih being in a new environment and Michaela became such hard work.  Having someone who she's not used to and is dissimilar to the type of people she is used to invade her environment (i.e. family staying) is probably having the same affect on your DD.

Once we were home Michaela settled back into her routine and became her lovely cheerful self again.  I hope the same happens for you after Sunday and good luck until then.

We just experienced a similar thing whilst having ALL the family stay for XMas.  Everyone would be repeating the same message to Tom so he would get told "No" but about 4 people all at once.  He was getting confused and wanting his mummy a lot but my MIL was trying to keep him from me to give him a rest.   He coped well but as soon as they left he started throwing tanties about EVERYTHING! 

A week on and we have our happy little boy back.  But I expect the wheels to fall off when bubs arrives.   You might find that toileting goes backwards when your bub arrives too....but I am sure things will come right.  Poor wee mite.