Don't be paranoid, but you never know when you might lose another, so spend time and energy with those you have left and enjoy it! I'm fortunate to still have my parents. I didn't even know them, really, for most of my life, but in the last few years we've really gotten to know each other well. It's been great, and I'm learning more about other family as well.
My relationships with friends haven't gone as well. I have one real friend left, and he lives 200 miles away. But we love each other and we get together when we can. We talk all the time. Don't fret over those you don't have anymore. You can't change that. But you can make the best of your relationships with those you have.
Remember the good times and shrug off the bad ones. Hope you have a nice holiday season, and be positive. You still have people in your life who care about you and who you care about as well. It's easy to fall into depression this time of year, but you can just as easily make it enjoyable. If nothing else, find someone who has nothing, and give them something. It could mean the world to them, and it would make you feel good as well. 
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