What is it you suspect he was given by the groomer?
I don't know whether or not the cigarette butt would make him sick, although I guess he could have developed a problem from the concentration of nicotine in the filter if he ate it. Is there anything in your home that he could gain access to without you knowing it? Human medications or anything like that?
For my own peace of mind, if I were you I would make an appointment and take him to the vet to have him checked out. A blood test / tox screen can tell you if he has something in his system that should not be there, and the vet can maybe come up with some suggestions as to what could be bothering him after examining him.
Whatever it is, if it's enough to make him act in any way other than his usual self, it needs looking into and a trip to the vet is in order. Better to be safe than sorry.
Ghilly
Y'know, I just had a thought. You said that he is better outdoors than indoors. Do you have a carbon monoxide sensor set up in your home? Do you live anywhere near an area that is known to have radon gas? Animals are a LOT more sensitive to these things than we are, and the fact that your dog is acting strangely INSIDE would make me worry that there is something in there that could eventually also adversely affect the humans in the family. Carbon monoxide detectors only cost a few dollars at places like Lowe's and Home Depot, and I believe there is also something similar to detect radon gas. I would look into checking your home out for those things as well. You can never be too careful.
Ghilly
There are also many other indoor chemicals/perfumes/smells/ noises, etc, which could possibly affect a dog. Something which could affect animals are the very high-pitched sounds from electronic equipment plugged in or on standby, including phones. I can hear them, but a lot of people can't. And if the noises are always there in the background, even someone with very good hearing would probably not notice them. After a while, those noises irritate me, and would make me want to stick MY head under a blanket! If I can hear them, I am sure a dog will hear them at least three times as loud!
Great points on this thread. Another one for indoors is ozone from printers. I can sniff a whiff of ozone at 50 paces, and my husband has no clue. I can always tell if it's going to be a bad allergy day the second I walk outside to get the paper. Indoors, many printers exhaust ozone, and some have filters that need to be regularly replaced. Not everyone can smell ozone, or is sensitive to it, but there are plenty of people and animals who have difficulty with it.
Another environmental problem that most people don't think of is basic cleaning indoors. Dogs have many of the same allergy problems as people - dust mites for example - so keeping your home thoroughly vaccumed can help. Household cleansers for floors can sometimes be a problem. After you wash the floor, the dog walks on it while it's still wet, and licks his paws thereby ingesting the cleaner.
Nadia, I hope you will take your dog to a vet as well as check on the carbon monoxide detecter. If it does turn out to be CO, your dog may have just saved your life. :-)