Today, I was thinking/wishing I hadn't started this thread, feeling embarrassed to have revealed this about myself. Then, to my surprise here, I find many kind answers, as well as others here who identify with the same problem.
Truegrit, actually my job is what gives my life meaning and the much needed structure. But, as you say, there seems to be something in the personal chemistry that is affecting this increase in isolation. I do take an antidepressant, and have used one form or another of the SSRI's for 17 years. I suspect there is an aspect of apathy that goes along with the meds for me, but I tried weaning off the stuff last year, after a two-year very gradual tapering down. I found myself weeping uncontrollably daily, unable to sleep, feeling increasingly paranoid, so I went back to the antidepressants.
I honestly still like people, and I'm not a shy person. Part of it is that I've learned to recognize situations which create anxiety within me (a problem since childhood), thus choosing to abstain from such.
Also, I used to desire to travel a bit, whereas now I engage in a lot of negative self-talk about why I can't or shouldn't. This attitude was part of my parents' constant interaction with me. I overcame that most of my life, and now at 59, parents deceased, their fearful and reclusive attitudes seems to be gaining presence in my thoughts.

OH, well, as Byz suggests, it really doesn't feel too bad being this way. And I still feel I have the option of choosing otherwise. That is something to remember, Truegrit...We still have the ability to choose.
Love and thanks to you all!
Patty