Change of plans?

The Girl has been home for the past few days (and the last few weekends) working as an aquatics instructor for the city.  This coincides with the end of the semester and her studying for finals.  So this is my dining table:

That girl has more on the ball than I did at that age.  

In the midst of getting the spare room shaped up for her to spend the summer with us, Firstborn called to say he might need to stay with us for about 2 weeks.  This throws a wrench into the spare room plans...I think someone will be sleeping on the couch...and we will be back to six people living here, all needing to take showers, get fed, and park vehicles out front.  I don't know why, but this change of plans throws me for a loop.  Maybe I'm just tired from my workweek.  But this is stressing me out.