My son is the SAME way! Would drink out of dog water bowls, eat whatever, nasty! We are on our second round of Humaworm, and did our first one when my son was 2. He was actually 34 pounds and we went camping on a lake and came home and was very sick. When we started Humaworm he was 27 pounds and had a pot belly. He stopped napping, had tummy aches, diarrhea, we could not figure out what was wrong and then found a tapeworm in his diaper. LONG story short, we ordered humaworm, did it and he past TONS of worms, and liver flukes (from the lake). We were all very grumpy the first two weeks from the die off. Whiny and complainey, he had tummy aches, but he started sleeping! He woke up happy and he ate SO much better after we started.
We are now on our second round...doing much better, still passing worms! Good luck! If you need anything, we have been through it with small kids!!