Im on 0.5mg of cabergoline once a week for elevated prolactin not due to a tumor, when should i start to feel better?

Take twice/week: You need to take it twice per week. If you do, and the dose is correct, you should notice a drop in prolactin within 2-4 weeks. Whether that will make you feel better is unknown, as i don't know if your problem is related to or causing you elevated prolactin. Psychiatric medication is a common cause for elevated prolactin, as are tumors to small to image.