I’m not sure either. It doesn’t sound like you are by nature an introvert. You miss being comfortable around other people. You do have some friends. The fact that you describe being with others as an “ordeal” suggests an anxiety disorder. The way to find out for sure what you are dealing with is to talk with a therapist who can spend the time with you to explore the issues in detail.
As for coping strategies: Often progressive desensitization helps people with social phobia – if that is what is going on. But I caution you: Treatment should always be driven by a good diagnosis. Wonderful interventions aren’t effective if they aren’t targeting the right thing. That can result in a waste of your time and give the symptoms time to get worse. So please get yourself an evaluation before deciding what to do.
I wish you well.