I agree with the others, it is absolutely possible. A Lactation Consultant can help (Morton Plant has a great group of ladies) or you can contact LaLeche League (www.llli.org) Here's a quote from their site:
"I would like to resume breastfeeding after an interruption. How do I relactate?
Sometimes a mother decides to resume breastfeeding, whether due to an emergency when there is a shortage of other food, after a separation, etc. Often a mother can rebuild a milk supply very successfully, with patience and determination (and a cooperative baby). The Breastfeeding Answer Book, published by La Leche League International, recommends the following strategies for relactation and induced lactation, to stimulate milk production:
*Putting baby to breast to suck at each feeding and for comfort between feedings as often as possible.
*Using hand expression or a breast pump.
*Using a nursing supplementer (if available and if conditions are sanitary enough to make its use safe) to provide expressed milk at the breast while baby sucks at the breast.
*Taking herbs/medication that increase milk supply (herb resources are listed in the resources collection).
If you do use herbs or medications to increase your supply, be sure to put the baby to the breast frequently, to remove as much milk as possible. This will help avoid breast infections or plugged ducts.
Our FAQ on increasing your milk supply also contains valuable hints for re-starting breastfeeding, and our article on how the human breast works contains valuable information on how milk supply is built up and maintained."
You can also get information about herbs to increase milk supply (like fenugreek) at www.kellymom.com
Good Luck! And I totally relate to being surprised at liking the stay at home mom thing. I was the same way. Babies change everything.