It sounds like one of the things you are worried about is going from being competent at work, to bewildered by the PhD. Could it be that you change your approach to the PhD? I treat mine like a desk job, sit from 9-5 and work as I would in a work day. It helps me to split things into tasks and plan the week ahead, ticking off each (sometimes micro) task so I feel I have achieved something.
It is totally normal for you to not have a full idea of what you are doing yet-especially in sociology. A lot of a PhD is thinking and conceptualising, which you don't feel like as being work, but it is.
But, you are the one doing the PhD. And you know in your gut what is right at this time for you. If you, despite persevering, really deep down want to leave, then you don't need anyone's permission, and you will have other opportunities in the future which you may enjoy more.
Ultimately nothing is worth your mental or physical health being put at risk.
Slow progress is the nature of PhD. It is nothing like a Masters in that respect, and is really difficult to stay motivated.
I wish you luck in whatever you choose to do.