cat lethargic, not eating well and vomiting.

my cat is 8 weeks old last friday i took him to a vet for a check up and he gave him drops for deworming.

But since then he has had a loss of appetite.

He is active but tires early and then becomes dull.

last night he vomitted..

i have been feeding him Whiskas Tuna.

please help

Have you called the vet back? You need to call the vet again and tell him what's going on. Incidentally that is not the best food to be feeding your kitty. Others here should be able to give you an idea of what an eight week old should be eating but I don't think it's Whiskas tuna. Please call the vet as it's very dangerous for kitties to have loss of appetite but especially a small kitten. 

Agree with Finnlacey.  At a minimum, I'd call the vet and tell him/her that since he was dewormed, he's gotten sick.  (What dewormer did they use?)

Fancy Feast for kittens is a step up from Whiskas; you can find the kitten formula in PetSmart/PetCo (not as often at the local grocery store).

In any event, avoid fish, particularly for male cats.  Has minerals in it that aren't good for cats (among other reasons).

Let us know how he is

Welcome atif! I am glad you found us and I am going to reiterate the above. Bring your kitten back to the vet immediately. Always, always call your vet if you feel your kitten is having a reaction to a medication they dispensed or your kitten is not acting normal. Kittens can go from bad to worse very, very quickly. I would also suggest getting him on a better canned kitten food. Fancy Feast kitten pate is a good one and would be better than the Whiskas as Ritz pointed out. I would also avoid the tuna because it can become addicting and then your kitty will only want tuna or fish based foods. Best to stay away from fish and only give as a special treat on occasion. for your kitten. Please keep updating.

thank you guys for the warm welcome.

Got an appointment with the vet this afternoon.

He is much better today though, but will get him checked just to be safe.

I am from India and that to from a small city Whiskas  and Meo are the only two in pastes then there are dry ones

which one should i go for?

Let us know how he's doing. My cat had a bad reaction to a flea treatment once. His ears and paws were bright red, he wasn't eating, and he was shivering and hiding under the bed. The vet gave him fluids under the skin to essentially dilute it out of his system. He felt better within 24-48 hours.

sorry for the delayed reply but he is doing fine now, his activity and diet are  back.

thank you guys for the help.

So glad to hear that your kitty is better. Thanks for the update.

Sorry for the late post. Also glad to hear your kitty is doing better.