I was worried my Marcel would not make it past 2.5-3 lbs. according to the growth chart. And, at around 7 mths - he was probably about the same as your baby. I think at 10 mths he was just shy of 3 lbs - and I think right now he hovers around 3.4 and he's about 1.5 yrs old. So, sometimes these tinies do have later growth spurts - so hang in there, she may still grow a bit - probably not a ton, but a little more. And, like Nancy said - they can be just as healthy as any other size dog. They might have other vulnerabilities due to size (like, falling off of a couch etc.) that you have to watch, but they can still be totally healthy.
