How many hours of stages 3 and 4 NON REM deep sleep do I need a day? I am dreaming a lot and feeling EXHAUSTED and weak.

Intelligent question. but it doesn't work like that. Stages of sleep develop, and then start all over a few times every night, and are not usually summed to a whole. But you may need a sleep study. In any case, check with a professional about not restful sleep.