I have never had a pregnant dog, so I am no help. I would think that she would gauge herself as to the activity level she can stand, though. Perhaps if you feel it is getting too rough, you should separate them for a while. I think speaking with your vet about this is probably the very best thing you could do, though.

I assume this pregnancy was an accident. Hope you'll get the info on having her spayed as quickly as you can from your vet when you talk with him/her.

Good luck.

Logan