Make sure that you are feeding your cat healthy cat food that has all the nutrients in it. You may want to ask your vet if you should change the food. We got a cat from a previous owner. She has long white hair and blue eyes. She was only 7 pounds and 5 years old. We started feeding her Iams cat food and she has gained 3 pounds and the shedding is getting better. She is not losing as much and she is more active now with the extra weight. She was so thin before that I didn't even want to pet her (felt all her bones).
I relate COMPLETELY!!!!!!!!!!! Our mama Princess shed so much that sometimes I don't want to pet her. I got her a brush where the bristles bend a little at the ends, and it works wonders. I had to brush her for about 20-40min the first time, haha, but now a 10min every few days does the trick. Keep in mind also that spring and fall are the worse times for shedding. They're getting rid of their winter layers right now. Princess is our long-haired cat, as well, and they tend to shed more than short-haired cats.