Hello, welcome to JustAnswer! I am a licensed veterinarian, and I'll be happy to help you in any way I can.
A young puppy, who is lethargic and drooling, may be hypoglycemic (has low blood sugar). This is common in young puppies, especially if the pup's appetite hasn't been good.
you can try to rub some corn syrup or honey on the gums and tongue, to see if Bullet perks up at all.
there may be underlying issues such as parvo virus, or distemper virus, which could contribute to this situation.
therefore, if Bullet doesn't seem to perk up and eat and drink, within 1 hour, you will need to have him examined by a veterinarian.
this situation may be life threatening, so it is important to not delay, if bullet's situation doesn't rapidly improve.
he has now started to make a grunting noise now and again
grunting may be a sign of discomfort, or difficulty breathing. either situation warrants concern.
is there anything else i can try as dont have corn syrup or honey
that's about all... otherwise you need to seek veterinary care, or Bullet's life may be in danger.
im gonna ring the vets now thanks for your help
you're very welcome - I wish you and Bullet all the best.