Had a baby! How to re-train the dog...?

I had my first baby in January. I have a 2 1/2 year old spayed female Lab/Brittany cross who was somewhat shy and a bit of a nervous barker before the baby. She was very well trained, however, and responded reliably to our commands. Now that the baby is home she has become mively protective of not just my daughter, but us as well. She barks at falling leaves, bullies the cats when they go near the baby, and acts extremely nervous and jumpy all the time. When people (even people she knows) enter my house, she growls in a menacing way for several minutes before she'll stop. It has been endlessly snowing and cold here since the baby's birth and we haven't been able to work the dog outside as much as we'd like- not to mention getting 0 sleep with an infant. Any suggestions on how to take the edge off my dog and get her to relax a bit? I want her to protect my child, but this is a bit too much. Thanks for suggestions!