Does anyone else feel comfortable by themselves but isolated at the same time?

Yes... and also no.

Sometimes I can be perfectly content with my own company, but then I'll go through phases when I don't and will feel desperately lonely, despite having an adult child who lives with me.

I was trained conditioned etc not to admit I feel lonely (or anything else for that matter, we should show no fear or pain i.e. regimental). I'm starting to allow myself to admit such things to myself(and even others) but is still pretty alien to me / 'unacceptable behaviour ' / signs of weakness 

I was trained conditioned etc not to admit I feel lonely (or anything else for that matter, we should show no fear or pain i.e. regimental). I'm starting to allow myself to admit such things to myself(and even others) but is still pretty alien to me / 'unacceptable behaviour ' / signs of weakness 

Yes, onwards and upwards 

In that case, I'm happy you're relishing the freedom to be your authentic self and free yourself of those shackles.

It's exciting too, like being a kid in a candy shop (for the first time also) at times too, potentially+hopefully  I'm glad to hear you're aware you feel sad and lonely as opposed to unaware (suppressed, repressed, numb, disconnected, desensitised, tuned out etc like I've tended to be so far), if you see what I mean 

I find it sad that you were conditioned to suppress your feelings, and can only imagine how difficult it must now be to 'unlearn' that conditioning.