I would say it is probably quite normal for the pup to be lethargic for a day. The meds given to get rid of the worms is poison and in order to kill them it will upset the pup's stomach. Scramble up an egg and feed it, it seems to act as a way to get the remainder of the poison out of the pup's system. Make sure she drinks water and if not better in 24 talk to your vet again.
In the past I have rescued pups that were dying from roundworms and this always worked for me.
If your dog was throwing up due to worms I'm sure it feels pretty sick. I would call they vet and ask when he/she should start to feel better. You could try and feed some cooked white rice and chicken broth, thats easy on the stomach. The not drinking part would scare me more than the not eating.
I would definitely take her back to the vet. Or at least call them and tell them what is going on. I worked as a vet tech for the past 4 years. The only thing we ever gave through an IV for worms was fluids if the animal was dehydrated. That wouldn't neccessarily make the dog sick. However, if the worms are dying from the deworming she may have an upset tummy. If she's not drinking then she could become dehydrated again. I would definitely call the vet and have them tell you what to do.