At 44yo, how do I meet n make friends when I'm self employed, live out in the country, etc? Lonely & sad all the time

Many opportunities. I hope you'll seek out various ways to connect with others. Consider joining organizations to contribute through volunteer work, being on a board, etc. As you know there are churches, health clubs, various social groups, online chat rooms, etc. If you feel a lack of desire, down, and immobilized, perhaps you should begin with a visit to your doctor for a good exam.
It can be hard. To meet people when you work by yourself and live in a remote place. I would suggest looking for a church or events in the largest town within an hour or a bit further from where you live and start going at least once a week. Volunteer to help a charity. Or take a class at a college once a week. It will lead to meeting new people and feeling less isolated.