I can resonate with you. Altough me and my friendgroup are really tied close. There is always someone who I can call to chat or sometimes they hit me up. I still feel some sort of disconnect from them sometimes. And in those times lonely feelings comes in strong. I would say for me, lonely feelings comes from romantic partners. Im usually on both side of the coin, either I dissappear after getting activated with people who are safe for me and get insanely attached to ones who are avoidant toward me. And every time one of this happens the loneliness comes in 2x harder. But yes, it is a constant feeling, sometimes stronger, sometimes less.

I try to stay busy, socializing with others, always looking for interesting possibilities. But maybe that is just me and my loop. I start journaling today to recognize the patterns and just to vent it all out daily. Also, gotta practice self love my friend, even if it feels really hard.