Changing careers. Get me outta here

I've had it. I started nursing later in life. I'm in my forties now and find I just can't do it. I thought I could but find I'm not comfortable with the amount of self doubt I have. I am a LTC nurse which I love. Recently started in a home where I work alone and no one else around to ask questions of. It's lonely and scary. Things eat me up. I'm scared of making the "fatal mistake". I'd like to leave my job and just carry on with the rest of the day instead of beating myself up. What's happened. Can anyone share some insight. I'd like to start anew but not sure which way to turn. Give me the biggest rock to crawl under please.