Hi - I've been watching your thread on pins & needles right along with you to see if your girl was indeed pregnant. Looking at the pictures you've posted I was thinking you might have a false pregnancy going on, but I guess at 10+ lbs. and carrying only 2 puppies, she's got plenty of room to hide those babies in there. Congratulations on your exciting news & I wish you much luck with the whelp.
The temp drop is a good guideline, but can also drive you crazy as sometimes it will go up and down, up and down. But a drop is definitely a sign that labor could happen within 24 hrs. I have found that I've been able to notice a definite temp drop by placing my hand on her belly; it will be obviously "cooler to the touch" than it has been. Their bellys are pretty warm all through their pregnancy. I learned about that trick on one of the canine pregnancy calendars that gives you week by week pregnancy progress. My girls have always gone off their food the day of or before whelping as well.
I am kind of in your situation right now....wondering about one of my girls, who is likely 5 weeks along this weekend. But as I do with each & every time, my mind seems to like being a non believer until it is very obvious.
But with any luck, we should be having our litter of Biewer Terrier puppies in mid November.