I can tell you how to fix this. Cultivate a deep and meaningful relationship—with a girlfriend. Yes, that’s right, a friend. One of the things that makes us lonely as a single person is we don’t have anyone to witness our life day in and day out—so change this. Get a girlfriend who’s single and wants the same thing (or close) that you do. You two can support each other, check in on each other, and make a structure to witness your lives together.
Find a nice, single woman who’s fun, compassionate, loving, and can listen to you tell her about all the highs and lows of your life. You should be ready to be that for her, too. In fact, find two or three new friends. You do that, and you will not be lonely. You’ll be one of those happy people who happens to be single. Having this structure doesn’t mean you don’t want a relationship; it means you can find happiness and meaning in your life regardless of your circumstances. And hey, do you know who makes for a really good partner? Someone who knows how to be happy in her life, regardless of her circumstances. There’s really nothing more attractive than that.
Good luck, and for more, take a read through my article 10 Life Changing Habits Happy Single People Do Every Day.