Oh dear, that does sound hard. Golly.
I sure hope that your today is better. Sounds like you deserve a break.
In my own opinion, You can be a totally whole healthy happy person who is happy all alone AND STILL FEEL A LOT OF ANGUISH ABOUT LOSING YOUR MATE. We're born to be physical and warm and to feel communion and rapport, and this is your birthright.
It doesn't necessarily mean that you're lacking anything.
My two team mates here, pj and Mr. Number Guy, have good enlightened ideas. I'll just kick in my 2 cents' worth that there's not a thing wrong with being a loving responsive person who has the incredible capacity for bonding to another person. Not everybody has this, so what a blessing that you are feeling these feelings.
(Oh great, Autumn. Thanks a noodle.)
Well, but your sincere post suggests to me that even though the bonding-person is not in your life today, your bonding-valence is still intact and whole and alive. That makes today a lot more painful, but tomorrow a much more hopeful place. That warmth you feel is not just a terrible joke with fate laughing at you. It really means that you saw something good and were open to it. And, you can be open to it again!!! Pain is not a failure. It is a sign that you and your life are changing very very fast.
This might help, or it might not, and if not just ignore it.
But at some point, I'd be eager to hear the qualities that really made this person most special to you. Perhaps crystallizing it will make it even easier to find those qualities in the world around you again.
My heart goes out to you in this vulnerable time!