Don’t be afraid of loneliness; don’t be afraid of too many people around; don’t be afraid of sharing your life with an SO you think you don’t really know. As you age, these phases tend to blunt and blend together, like the seasons. The only thing you really have, in the end, is yourself.
Adult life is a lot more about compromising than fighting. Don’t make other people’s life shitty on purpose, neither allow them to make yours shitty.
Get your regular medical check-outs.
Leave a place if you positively can’t stand it any longer, and start from scratch. It’ll be okay.