Who shrunk my shirt?

You know your day isn't starting off the best when you get dressed and realize you shrunk your shirt about 5 sizes.  I literally looked at myself in the mirror for a few minutes trying to figure out how I could have possibly done that.  The only other explanation was that my waist grew several inches in length during the night.  I was at a loss until the words of grif from earlier in the morning popped back into my head "mom, where is my aggie shirt?".  I was wearing an 8/10 year old kids t-shirt.  When the crap did my kids get big enough that I could confuse their clothing with mine?