Worms can cause a dog to vomit. However because she is vomiting after you gave the med, I think I would hold off right now.
We treat worms IF we diagnose worms. That is done with a lab test. I do not like to treat any
animalAnimal shape vitamins
Animal shape vitamins with iron based on a guess.
Your dog may very well have worms, but we need to know WHICH kinds of parasites and then give the med that kills those worms.
Further, your dog may not have worms at all. Could be a GI condition that is now progressed to vomiting etc. In a GD puppy I would not take a chance. Both the GD and the German Shep are known for serious GI problems. I think an exam by your veterinarian is necessary and soon.
After you do this, check back here and let us know what you found.