I think lonliness may be the deepest pain on earth. I felt like you for years... All my life really. I only recently noticed that I have not felt lonely for several months... It finally faded away without me noticing. It was counterintuitive - I believe often the way to overcome lonliness is to take a chunk of months and be alone as much as possible, go through the pain, not around it. And make sure that any moment with people is a high quality, connective, intimate, nourishing moment (aka dont waste your time with fluffy people, and share your most intimate thoughts and feelings with people who love you vs having surface level "how was your day" chats.)
Feedback from those who embrace you in your vulnerable state really chips away at loneliness in a profound way. BTW support groups are great for this too.
I would take it step further and say to the best of your ability, never* do anything you don't want to do. Over time you will stop feeling guilty and you will get more in touch with what you really want and need, and the oxymoron of loneliness will start to fade. Find out who you really are without* all of the highly aggressive, judgmental social messages about what moms should do and be. There is way too much nonsensical pressure on moms, who are in the process almost expected* to lose their whole identity. Its like a culture-wide abusive relationship. Society wants moms to be robots who have no self, no personal needs or goals, they just become a shell whos only existence is the serve a child. Isn't this called "battered woman syndrome" !! Its dangerous and wrong. All that to say, never feel guilty.
You're human and you have your own very, very important needs which have to be met for the sake of your health and sanity. And that does not often include soccer games or social events or whatever.
