Think this is what is known as existential lonliness. You could have a thousand girlfriends, friends, money, the loneliness would still persist. At least you get some reprieve in that it doesn't seem to hit you when you're with people, but rather when you get home. I don't think trying to drown it out by talking to more people would help. Perhaps deepen the connections you already have with the people in your life. Can you talk to them about this type of lonliness? If not, then that shows you could develop the relationship some more. Or perhaps you need to spend some more time with yourself, alone. Find ways in which you can enjoy your solitude. I can relate to the paranoia though. Someone could be with me for fifty years and I'd have to keep checking whether or not they secretly hate me.