Long-term loneliness sucks.
You either get depressed, cynical, destructive or delusional.
Since I decided to be less cynical, I get more depressed and it's no fun but it is said, that cynicism would scare away the wrong people if they existed.
Being in open spaces a lot for a few years and making music in parks sometimes didn't change anything when it comes to the lack of offline contacts.
Everyone here is giving good advice.
When I give my advice on this subject - people don't want to hear it. Because it is hard, very hard.... and perhaps almost impossible for human beings (I don't know... all I can say is I have achieved it.... but the jury is out on if I actually qualify as a human being)
I can't tell you how to achieve all these points... it is a personal journey for each:
1: Unravel your personal motivations. Identify where you have been conditioned (where have you adopted beliefs from outside sources - parents, peers, media, school, 'secret schools', etc). Anything that didn't come purely from you, no matter how logical or sensible it seems... mark it down as 'suspect' and in all likelihood 'BS'... you will have to go through extensive introspection and experimentation to extract whatever truth (if any) there is in these beliefs.
2: Detach yourself from 'outcome'... from now on, the 'results' are not what you are aiming for... from now on the results do not matter.... the only thing that concerns you is what you put in... i.e. Your own quality, your motivation, your intention.... it must be on the quality of your contribution.... not on what you are trying to make happen or achieve (This is hard for humans to grasp).
3: Detach yourself from your own identity... practice experiencing yourself as a transient expression - that you are no greater or less than any other expression... come to know yourself as the being that expresses itself, not the expression. (In any interaction, when you remember, step outside yourself and simply observe how you behave and think... without identifying with either... most humans can't do this).
4: Nourish your form - as you would a beloved pet or creature or child for which you are a custodian... give it what it needs.... YOU in reality have no needs, but the form you have taken does have needs.... so determine what it needs and give it that.... not what it 'wants'... what your form (body, ego) wants is often not a real need but a gratification... the need for gratification coming from a conditioned dysfunctional sense of self that only provides temporary diminishing relief and leaves one with an amplified need for gratification after the temporary effects have worn off. ... In other words - addiction (which can take any form). Keep in mind that the entire human economy / social system is dependent on addictive gratification - co-dependant relationship especially... which the vast majority of human beings consider as 'normal'.
5: Put into your life more and more of what makes you feel 'light' and 'free'... cut out anything that brings you down, that makes you feel 'heavy' or 'restricted'.
6: Forget about making friends or getting into relationship... Your job is to become the best friend you've never had to yourself... and through hard work and dedication... enter into loving relationship with yourself.... You are both the egoic form, and the formless beingness... This is your great task, your number one priority... your constant meditation... your ultimate purpose.
Remember... focus not on the results, but on the quality of what you put in.
After some significant time working on this 'true' relationship, you will forget what loneliness feels like.