I'm so sorry you're going through this. I completely understand the fear you feel.
I'll start out by emphasizing what your own disease experience has shown you. This is typically very slow growing, giving patients alot of time to tackle things as they pop up. Yours didn't rear it's ugly head for 3 years! That's fantastic!
My husband was diagnosed stage 4 pnet 17 1/2 years ago and he's still here living life! After one net specialist told him to "get his affairs in order" another told him "nonsense" We can treat this as chronic disease. And that is exactly how it has played out for 17 years.
One thing to keep in mind that when reading boards, forums, Facebook groups etc you'll often only see stories from those currently struggling. The long term survivors often don't frequent these pages as they don't need them. So keep that in mind while reading in those places.
Secondly, I find taking control over the disease is important. You are not at the mercy of this disease. Take control by learning all you can about this disease and the available treatments. Be your own strongest advocate. If you haven't already, find and consult with a net specialist. This is crucial! Mayo has specialists at all 3 of their locations.
You can find more, listed by state at http://www.netrf.org
Lastly, I would urge you to seek counseling to help cope with your extreme emotions. Personally, my husband's outlook turned around completely when he turned his life over to God. That is where he found and continues to find the most peace and strength to carry on.
You may have to live a long life dealing with this disease. Don't waste that time in fear. Focus on gratitude every day. Be grateful for every day and every person in your life and every blessing in your life and enjoy every day God has graced you with.