Lab in heat?

Question
We have a lab that we found about a month ago. She has recently begun to act strangely. We are wondering if she may be in heat? She pants heavily and has stopped eating for the most part. (Dry food). She also has had some discharge as well. Today she began gathering stuffed animals from the kid's room. (NEVER done this before)And we have also found her curled up in the kids closet. Could she be in heat? Or even pregnant?? If she's pregnant, how can we tell?

Answer
The second and third weeks after the discharge starts are when the most risk of accidental breeding is.  Don't take this lightly.  She will do anything to get loose and get to a male.  Once loose, an accidental breeding and an unwanted litter is far from the worst that can happen.  Such breedings can also result in fatal infections.  She can get killed when she dashes heedlessly across the road in front of a car.  Other dogs or coyotes may kill her.  

You can expect the same thing about every 6 months for the rest of her life if you don't go ahead and get her spayed.  There is no other answer, and no good reason not to.  Besides saving the hassles, it reduces the chances of cancer later in life.  Please make life easier for yourself, her, and society in general by getting her spayed as soon as a vet will do it.  

Telling she is pregnant?  False pregnancies are very common and can be quite convincing.  About a month after mating an experienced person can feel puppies and vets have better methods.  Only a vet can give you good answers to your questions.