10 month old jack russell

Question
QUESTION: my 10 m month old vomiting at night. acts fine in the day, drinks plenty of water . has tons of energy, but vomits about 5 / 7 hours after injestion of food, no poop in 42 hrs

ANSWER: DO NOT WALK, RUN TO THE VETERINARIAN IMMEDIATELY.
THE DOG SOUNDS LIKE HE HAS A BLOCKAGE (PUPPIES EAT EVERYTHING, SOCKS ETC) THEY GET TRAPPED IN THE INTESTINES, TWISTED, COMPLETELY IMPACT THE INTESTINES MAKING IT IMPOSSIBLE FOR THE DOG TO POOP AND CAN TURN DEADLY VERY QUICKLY!!!!!   42 HOURS WITHOUT A BOWEL MOVEMENT IS DANGEROUS. GO NOW PLEASE.

---------- FOLLOW-UP ----------

QUESTION: 24 hours , got dyslexic.... but have withheld food to see if that is problem..

Answer
oh, you've withheld food.....
but 24 hours is still a very long time for a dog not to poop -
I would still take him to the vet, it still sounds like the food can't get past the stomach.
The "dyslexia" by which I think you mean confusion, weakness - can be caused by many things like
exhaustion, high fever, dehydration, illness.  It's time to take him to the veterinarian before
he gets worse Scott.  Wishing you both the very best of luck!!!