Cats can be very sensitive to their owners' mood and feelings and do often react to this in different ways like being more vocal and some starts to hide more, but for a cat to react by start to pull hair does normally take a lot more serious stress to the cat.
So in my opinion your problems are probably not the cause of the cat pulling out fur. The pulling of fur is a very strong reaction for a cat.
Stress for a cat is moving house or a new cat in the area and the loss of a friend (other pet in the house) or the loss of the caretaker, but I have never seen a cat pulling out fur as a result of this.
You do say the cat is using medication for renal failure, so it might be best to start finding the reason for the fur pulling in your cat's health and take him to the vet to get the bloodwork and tests done to exclude any medical reasons for this.
I do not think hiding your emotional state from the cat is a good thing. I think it is better to tell your cat about it both for yourself and for the cat, and cats are really good at keeping things to themselves. At least mine are.