six week old kitten vomits white substance

my six week old kitten has been vomiting up what i think is his milk. I've been feeding him and his sisters kmr. i saw some vomit around maybe three times and i just thought it was time to switch to solid food so we bought some today and he only ate a bit. i didn't know if it was just one or all vomiting but i thnk it is just him bc today he is acting different. he usually is a voracious eater and can't wait to get the bottle. i just noticed his tummy is less full than usual and than the others'. he ate a bit and then came to me to be carried. i will try to take him to the vet as soon as i can but idk about schedules and all so what do i do if he gets worse? what could be wrong? pls help. I'm very worried. i just tried to give him some more milk. he took a couple of sips and then didn't want anymore. then he went to sleep. 

It's possible he's vomiting up the milk. At 6 weeks they are all ready to start on solids. Begin with wet canned food and keep bottle feeding them for the time being. The first few times most kittens play in the food as opposed to eating it. You can dab a little on their lips/paws to get them to lick and see that it tastes good. I would also put out a big bowl of water and dry food that they can gradually start on. If you haven't already this is also the time to start litter training. If you don't have cans of food or want to make your own do a search of the site for kitten glop. There are a lot of recipes others have posted. 

As far as the vomiting, every now and again kittens vomit. Maybe he ate too fast or too much. But, if he's doing it a lot then it can be a sign of something else so you are wise to get him to a vet as soon as your schedule permits it. Vomiting can be a sign of an infection or a parasite (as well as other things those are just the most common). 

The main things to watch for is that he doesn't get dehydrated and doesn't lose weight. You can tell hydration by pulling up the scruff of his neck. If hydrated it should snap back into place. If dehydrated it will "tent" and take a lot longer to go back down. Also, weigh him everyday to make sure his weight stays up. 

If he is dehydrated, starts losing weight, becomes really lethargic and stops eating altogether you have to get him to a vet ASAP. Kittens go downhill very fast so time is of the essence if any of this happens. 

Good luck!

You got good advices by EB24. Myself I have a feeling, like you do, it is something going on there. As you hint he is more tired and more cuddlier than usual.  So yes, contact at least a vet by telephone, but if you do want to play it safe, visit the vet, "risking" he tells you to come back when it becomes worse so he sees more clearly what is worse.  Begin by phoning if you can ASAP, but visit is the appropriate here I think.

How seems his body temp? is it higher you think?

Good luck!

(ps  I asked a mod to take away the excessive posts)

thanks for the advice. he is okay.