What makes you lonely?

Up to about 35, I didn’t know what the exact feeling of loneliness is. The reason might be that there were always my family, friends, and co-workers who I could do with. I even was alone, I usually thought that time was too short for my study, work, and playing something on a computer or  smartphone.  However, I started to feel something that I couldn’t get rid of myself. I’d like to tell someone about this, but I can’t say to my family or friends.  For instance, I’m out of the orbit which the same aged people do, such as having a job and their own family. I’m really satisfied in my choice and life, but sometimes, I am unnerved and lose my way. I want someone to share this, but I am a grown-up guy, too old to talk to my parents. My friends are so busy listening to me and have already got heavy burdens for their family. Mine is just a small thing. I may need one special person to be able to freely say everything about me and visa versa. That may be the sort of loneliness that I feel.