Very Worried

My cat is strictly an indoor cat, about 7 years old. For the past few days he's become very lethargic and not as social and friendly as he usually is. None of us have seen him eating for the past few days, but he has been drinking water. We don't know if he gets up during the night to use the litter box at all; we haven't seen him do it during the day. On the first day, if anyone tried to pet him or talk to him he growled at us. Now if we do it, he purrs a little but nothing else. 

Please, I could use your help. I haven't dealt with anything like this before and I am really worried about him. Any help you can give would be greatly appreciated.

What do you feed him?
Anything found in the litter box at all?

He could be blocked. It's not good if he hasn't eaten. He needs to see a vet ASAP.

The brand of cat food we feed all of our kitties (we have three) is Whiskas Hairball control with Chicken. The other two are okay. As for what's in the litter box, with three kitties it's a little hard to tell. 

I agree with Mosimom, he could be blocked and time for the vets.
ANY sudden change in behavior is a cause for concern. Cats can't tell you they feel bad, they can only show you. Growls of course. And, actually, purring: cats can purr when they are stressed, ill: it relaxes them.

You could try isolating the cat, with a litter box, wait a little bit and see if he urinates, though frankly I wouldn't wait that long. Note that if male cats become blocked, it is life threatening.
At the least he should be peeing if he is drinking water, maybe not pooping if he hasn't eaten. Try baby food (the kind with only meat and broth); most cats love the stuff. Also note that if a cat doesn't not eat for 24 to 48 hours he is at risk for developing fatty liver disease. Vet time, please!

He really needs to be seen by a vet as soon as possible. Not eating for several days, no matter what the reason, can cause a dangerous condition called hepatic lipidosis. A urinary tract blockage is also potentially fatal and can get very bad extremely fast.

My cat developed "fatty liver" & did not eat due to the nausea. I detected this early enough that she recovered, but was told that many people wait too long. I would not delay getting kitty to the vet, especially if if he's gone from growling to listless. At the very least, give them & stress to them how unusual the behavior is (if it is) for your cat. Sometimes they need to know it's really an emergency so they don't make you wait another week for an appointment. The same is true if it's a blockage. Best of luck!

Very sorry, meant to say "...give them (the vet office) a call..."

UPDATE:  My kitty has come out of his cubby-hole and he has walked around a bit, drank some fresh water from the bathtub tap, eaten a few bites of kibble, and hung out with us in the living room for a bit before going back to his cubby hole to rest. When I pet him, he purrs but he doesn't purr all the time. If I touch him on his flank, he protests. He moves around gingerly, with effort. My friend thinks he has a kidney stone he's trying to pass. We emptied out the litter box completely and replaced all of the litter. He was the first one to use it after we did that. He has urinated but he has not pooed. I am going to try and get some wet cat food and maybe some baby food for him, see if he eats that. I should make it clear that this is the second day of his "feeling under the weather" behaviour. He seems to be a bit better but we are monitoring him very closely and I will make arrangements to take him to the vet if he worsens.

I wouldn't wait if I were you..The quicker he seea the vet the better it'll be for both of you. Don't wait trying this that and the othe. Take him urgently to the vet.

Theres something wrong and the best thing to do is have the vet check your cat out. He's in some type of pain. Not eating much. Hiding out cats hide when not feeling well.Not as loving..Best go soon

ALL of these symptoms point to the fact that something is wrong with your kitty and vet help is needed immediately.  Kidney issues are very serious in cats and can cause death.  The fact that he is protesting when you touch his flank is a big red flag that he's in pain and as the owner, you need to help him feel better.  He needs to get to your vet or the ER vet NOW.  Don't wait it out, get him help now.

Jill you'll notice you're getting a lot of this feedback and I'll repeat it, you need to get the cat to a vet NOW.   A kidney stone can be life threatening for a cat.  But so can something he ate that has him blocked so he can't poop.  In fact if your cat is showing you he's uncomfortable you can be assured that he's really, really uncomfortable.   Cats hide pain really well.  Getting there early will preserve a lot of your options if he is sick, if you wait there may be no way to save him. 

Hi. I hope your kitty is feeling much better. Did you take him to a vet? As many of the above posts have stated, your pet does need to see a vet. It is only a vet that can help to properly diagnose your loved little kitty. I hope he is okay and feeling much better.