Hi nice to meet a fellow Canadian and only 1 province away!!
So not to scare you, but hopefully others will chime in and give their opinions as well as i am fairly new, but have had 2 snakes with similar behavior to what you describe....and the problem was RI...respiratory infection.
The first snake we dealt with RI in was a garter and we had no clue about RI, how to spot it or what could cause it. Due to this, we finally clued in to late and she was not able to be saved.
The other snake was one I bought from a "small time breeder" and it came ill with RI, so I immediately sent it back and luckily got a full refund.
Some of the first signs are less active, less flicking of the Jacobson organ(tongue), head propping or holding up. The snake does this as it is harder to breathe with the infection. It is easier for them to be less physical (less work breathing) and holding the head up also makes it easier for them to breathe.
In the first stages of the infection, they will still eat just fine, and of course be able to poop fine as well, as the infection goes on the eating will become harder. Things you need to look at are:
1. what are her exact temps, warm side, cool side?
2. what type of substrate are you using, some substrates can cause RI's
3. hold her near your ear in a perfectly quiet room, can you hear a funny, clicking type noise or a wheezing?
4.watch for the snake taking large deep breaths
5.watch for the snake to be gasping when breathing(breathing with the mouth opening)
6.watch for the snakes appetite to start to decrease
What can you do?
1.increase temps on warm side to 90F or 32C, this will increase the snakes metabolism and help it to fight the infection
2.get the snake to a vet, esp if there are any of the other signs, listed above, the earlier and RI gets treated the better the results, less chance of death or damage to lungs
3.make sure you are not using a substrate that is dusty, the very best substrate to use for corns is Aspen
4.humidity is generally kept about 30-40%
5.try not to stress your snake the more stress the harder for the snake to fight infection
6.I do not know how good of friends they are but if there are other symptoms, or if you are worried they sold you a sick snake I would suggest returning it and asking for your money back
The sick snake from the "small time breeder" that I got the sick snake from was from Fort McMurray AB, if by any chance you got your snake from someone from Fort McMurray AB and are concerned you may have bought the sick snake I had feel free to PM me and I will let you know where I got it from and returned to.
I hope this may have helped and if I missed anything jump in guys, I am fairly new and have only experienced RI or RI symptoms with snakes twice.
Tisha