Dog pregnancy

Question
OK so today is my Labs assumed due date. Well last night we were almost sure it was time. She began to pant (even though she had no prior exercise) we took her to the same room as her welping box and just sat down with her and watched TV untill the time came. Well during the time she would sit and lay down and relax and then like a while later she was up and paceing around and then would rest again. After 45 min she would get worse. Relaxed and then when she got up she didn't just pace and walk around she would jump up and wimper and run all over. and then all of the sudden she would lay back down and relax it went on like this for a hour and then nothing she was fine from that point on, we thought it might happen again in the middle of the night and she might give birth then, but nothing happened during the night. But today at about noon she was gaging and burbing funny like she was trying to barf, she hadn't ate anything since the other day (breakfast, didn't eat her dinner) so I didn't think she really had much to barf and she didn't barf and was fine after that. We think she may have them today and soon. What do you think?  

Answer
If she was visably having pain for over several hours and was very restless without any puppies she may have the puppies stuck in the birth canal...take her in to the vets asap...within an hour or two so I mean right away..unless the pups are here by now. You want to be sure she isnt have problems and is indeed going into normal labor before stopping panicing, best of luck to you and your big girl and her litter.