When a woman is excited, she becomes lubricated. The more excited she is, the more lubricated she is. Yeast infections also cause more lubrication. A woman who is more lubricated than normal may feel "loose" since there is less friction going on.
Strat, unless you're as big as a toothpick, and her supposed camp lover is the size of long dong silver, I highly doubt you'd feel any difference do to any stretching.
I'd chalk it up to her being REALLY happy to see you and therefore becoming highly "wet", and if she does indeed have a yeast infection, twice as lubed as normal. The lack of friction is what you sensed as her being "stretched."
Take a chill pill, and give her the benefit of the doubt.