Sorry to hear about the diagnosis for both your girls. That's so sad and scary! If they're both still doing okay and not struggling right now, I guess best thing to do is just enjoy each day, love them and spend as much time with them as you can.
I had this same feeling for my previous baby. At the time, I had no idea dogs could live passed 15 yrs (during the pre-Internet days). I read in a couple books that dogs lived to 8 or 10. So when she hit 8 yrs, I was SO sad...thinking she was going to leave me soon. But she was relatively healthy, despite needing medication for her heart murmur and medication to relieve joint pains. Each year would pass and I would cherish it to the max. She lived until 19, which was quite the shocker!
As others mentioned, I really don't think it gets easier. I personally grieved the loss of my baby for 3 years...before getting my two current ones right now. I wish dogs lived the same number of years as humans do
