My husband and I have a wonderful 3 to 4 year old tortie we adopted from the Humane Society 2 years ago. She's had all of her vaccinations and checkups and there weren't any indications that she wasn't a perfectly healthy kitty.
In the last few weeks she's been eating less and losing weight (which the vet wanted her to do anyway as she wasn't fat, but needed to lose about 2 lbs to be at her optimal weight). We attributed it to switching out her treats for regular cat food (a different variety than her every day food). She had a cough now and again, but we thought these incidents were normal hairball coughs. My husband noticed late last night she seemed to be breathing hard, so we planned on calling the vet to set up an appointment. By morning, she was heaving and her breathing was alot more difficult and we rushed her to the vet.
The vet thinks she's in congestive heart failure. She prescribed a diuretic and a heart medication, and we have to take her back in for more xrays on Tuesday (because of all the fluid in the chest cavity they couldn't even see the heart). They're going to call us with the blood test results tomorrow to rule out FIV, hyperthyroid, and heart worm. The vet doubts it is any of those and believes it is primary cardiac disease - that she just was born with a bad heart. If so, she will probably only live 6 to 24 months, and we might have to have her put to sleep if the medications don't control the symptoms enough to make her comfortable.
I'm a mess (so is my husband). We both were just sobbing at the vets and during the ride home, and on and off all day. Seeing him cry made it scarier somehow. I've had a bit of a problem today with carb binging (even though logically I know that no amount of "comfort food" can comfort in this situation).
When we got home kitty went under the couch and didn't come out all day. We had to get her out for her evening medication (actually my husband's friend had to do it for us, as we can't bend or lift to get under the couch). When he handed her to me, her chest and belly were damp - she hadn't had the strength to get to the litterbox and had peed on herself. She seemed to have gotten more on herself than the carpet, so she must not have even had the energy to avoid getting soiled. She was still pretty groggy from the sedative they gave her for the xrays, so maybe it's not as bad a sign as I took it, but she's such a clean cat, if her litter box isn't meticulously clean, she will normally sit beside it and mew until my husband or I come and scoop. Her breathing is still a little rough, I feel so bad for her, and so helpless. She seems alot more comfortable since she got her evening meds, but I'm struggling.
She's really become more of a child substitute for us than a pet. More than a child too, really because she often treats us like we are the babies (she reminds us when it is time to wake up, take our medications, meals, and bedtime), which is why we call her our "nanny cat." She loves people (even begs attention from UPS deliverymen and any stranger at the door). She likes herd us into the same room, and once she woke my husband David, during a low blood sugar episode by batting at his face in the middle of the night (something she never does). I have fibromyalgia and arthritis, and she always seems to know what joints are hurting and lays on them, my own personal heating pad. I really don't know what we'll do without her.
I don't really know why I needed to share this, maybe to relieve the burden a bit, and to remind myself not to eat everything in sight.

I can definitely sympathize with you. We lost our beloved cat, Puddy, a year ago. He went into Kidney Failure and we had to put him to sleep so he was no longer in anymore pain.....



Awww, so sorry to hear!
Take it easy on yourself, it will take time.