puppy not acting like herself

Question
I have a 6 month old black lab puppy who is very energetic and playful.  On Sunday afternoon I took her to an off-leash dog park for 2 hours.  As soon as we got home, she fell asleep and slept all through the night.  Monday, she slept most of the day, and when I got home from work, she was not her usual hyper self.  She fell asleep on my lap within 30-45 minutes.  This morning she was hesitant to eat and I had to hand feed her.  Tonight when I got home it's been the same thing.  She hasn't wanted to play, she's extremely docile and she just isn't herself.  All of her bowels appear to be normal and she isn't vomiting.  What could be wrong with her?  I'll be taking her to the vet first thing tomorrow morning, but is there anything I can do to make her more comfortable now????

Answer
At this time I can suggest nothing, but what you are already doing, let her sleep and talk to the vet in the morning. puppies have a variety of health issues just like Children they can contract canine versions of the "common cold" which can have slightly differing effects in different individuals. Observation of the condition and emergency consult with a veterinarian is recomended if the condition worsens.