Hi Chantel,
Dont worry too much. A while back, we had a litter that I gave the 2 pups away to my sis in law and her neighbor. They had very very rough starts (almost died) and were extremely small. At 10 weeks they were about 1/2 the size they should have been. My gut feeling was that there was something wrong that just hadnt shown up yet. WELL....let me tell you, they caught up and are now wonderful lil mosters. They just turned 1 year old, and are on the small end of normal for the standard, both in weight and height, but they DEFINITELY are not dwarfs, nor did they end up having any health problems that we know of. They just got off to a very rocky start.