Stacy, I'm so sorry. This must scare you to death. As far as weight gain, don't be surprised if you drop 20+ pounds in the next week or 2. When my brother was diagnosed with CHF, he was in the hospital and dropped 42 pounds in 1 week - all fluid!
Now, girlfriend, I'm talking to you like a mom. Today is the day you have to start putting yourself first until you get this under control. Be clear with your family that you are now fighting for your life. Don't downplay this, because it's serious business and your family loves you very much and will come through for you. Yes, you can reverse it but not if you don't take serious steps to care for yourself. That means preparing foods that you have to eat to get healthy, even if it's not what hubby and sons like or are used to. If they want something else, they can step up and make it for now. Also, you need to have ample time for your exercise program. Once your heart has been struggling, it's vital that you strengthen your heart muscle again. So no more trying to work in exercise between cooking and cleaning. You come first right now. I'm saying this because I think it will be the hardest change of all for you - learning to say no.
You are really important here, too, and we don't want anything happening to one of our own. So if you need help, here's the place to come. And a big hug from me to you.