Witz, if she is in business then she knows that employees, even good ones like you, come and go. This isn't personal; it isn't that you don't like her, it's that the job isn't what you had in mind and your health is being impacted.
She will be disappointed to lose you but she won't be disappointed IN you. There is a huge difference.
You did a good job for her and are leaving your position in good shape for someone else to take over. Few people who leave jobs can say that. There is no reason for you to feel bad.
Now, (as someone says- Barbara?) go put on your big girl panties and tell her you're leaving. You can do it! :thumb:
Suz