~~Need HELP asap, 3 week old kitten constipated!!!~~~~~?

This can be toxic for him, and Im sure he feels very uncomfortable. You should contact another vet immediately! A vet is someone you go to for help, and their number one concern should be the animals. If they cannot give you an answer, they are not very credible! Call around! Ask to speak to a vet or vet istant, and see what they say. Go to the one with the best answer. A kitten, especially this little, should not be constipated for too long! Poor little guy.