Hello, I'm Dr. Deb.
I recently came online and see that your question hasn't been answered. I'm so sorry that you've had to wait for a response,but if you still need assistance, I'd like to help if I can.
Believe it or not, this behavior isn't rare: it's not terribly common but it's not unheard of either.
When cats start avoiding carpet and move around in a room by jumping from one piece of furniture to another, I assume that they've received a shock from static electricity buildup; this might be particularly true if you have a fairly active cat.
Since most cats have a high degree of intelligence, they don't want to repeat an unpleasant experience and, thus, avoid the cause of their discomfort--the carpet.
In time, most cats will venture down to the carpet again but how long this might take is variable between cats. In an effort to avoid a repeat episode once they do, you could spray the carpet with an anti-static product which should be widely available at hardware stores or online.
If your cat is food motivated, you could try and tempt her back to the carpet by placing a small amount of chicken or tuna or Pounce-like treats there. Basically, try to establish a positive association with the carpet as opposed to the negative one which she now associates with it.
I hope this helps although, again, my apologies for the delayed reply. Deb
I wouldn't necessarily expect a negative encounter with carpet to cause her to be quieter; that's not usually what owners describe to me when their cats engage in this behavior. They're fine except they just won't walk on the floor.It wouldn't surprise me if it changed some of her behavior, though, where she wouldn't be sleeping in her usual places but that also depends on where she usually sleeps. If she's been really spooked or traumatized in some way, she might act strangely for a while.She's a little on the young side for an underlying medical issue to be present but I've seen some cats behave oddly when they have high blood pressure. Hypertension is usually secondary to kidney disease, hyperthyroidism or diabetes...all not likely to be present if she has no weight loss, increased thirst/urination, or change in her eating habits.And, I suppose it's possible that her avoidance of the carpet has nothing to do with a perceived lethargy. If you have a thermometer, you could take her temperature although this isn't always the easiest thing to do in a cat. Normal is between 100 and 102.5 F. Deb