2 month old puppy lost appitite

by Janda Nel
(Widnhoek Namibia)

Good day,our 2 and half month old puppu just lost appitite yesterday.Not eve drinking milk or water.He does not walk around much now and were very energetic before.He vomits a few times.

Can it be he teething or wat can the problem be.He has 2 sisters from the same "litter".They eat the same food,but he is the only one that is sick.
What else can it be?
Thanks