Why is my dog acting insane after worm medication?

I discovered my 7 week old puppy has tapeworms, so today I went to the vet and he gave him some medication. When we got home, he was fine until after i fed him his dinner. He eats the same dinner everyday, so I don't think it's the problem. He yelping, growling, running really fast and hunching over. His eye's are open REALLY big and he looks like he's really out of control. He's barking everywhere! What's going on? Does he have a tummy ache from the meds and worms?

Call your vet or an emergency vet. It's possible he's having an adverse reaction to the de-worming medication.

Call your vet or an emergency vet clinic. Have the information from the medication on hand. It may be a normal reaction, your dog could just be reacting in a crazy fashion, but he may be having an allergic reaction to the medication, or his condition may be worse then what was originally diagnosed.