If you accept that it's possible to feel alone in a crowded room then yes, I'm in your club. There's nothing like being surrounded by people who are in to 'family' including two overexcited 3 year olds and a baby when it comes to making me feel like I failed at life, and that's how I'll be spending today and tomorrow (and yesterday...)
If you mean longing for a relationship then no, but I'm jealous of you tp4 - at least you know what you want so have a chance of getting it.
And in preparation for my happy face wearing day - Merry Christmas everyone 
This situation might be completely psychological..
Because one really only feels alone when one goes into contemplation about it..
What is alone ?
What do other people have ?
What connections am I missing ?
Why am I not connected ?
Is there a purpose/ benefit to these connections ?
The cause of this may be due to living modern --Sufficient-- lives, with complete homeostasis.... All of the inter-personal dependencies are not truly there as long as we all have enough to eat..