It could be. When she is in labor she will start to nest and she will get nervous and her stomach will get hard and then go back to the way it was. She will start to pant a lot and be uncomfortable. When she starts to push then they will start to come. Be with her for the whole thing thy need your support and for you to assure them.
This is TOTALLY normal! I suggest getting her to a whelping box A.S.A.P. She is in hard labor and delivery is close. She will move in circles , whine, heavy panting and then she will stop, her tail will come up as her water breaks. She will lick her vulva and lick up the fluid and shortly after deliver. It is also good to talk to her and reassure her. There should be another pup with in the hour. Hope this helps. Good luck!