Had a hysterectomy 3 years ago. Now I have no energy what si ever. I used to be full of energy what could be the problem?

Hysterectomy. The first question will be. Are you taking hormones. Frequently after this procedure act like menopause state, where the hormonal levels going down and you can feel like that. A lab test hormone levels, /thyroid , adrenal, anemia, with a physical exam can help to determine .No necessarily your fatigue have/to be related. Go to pcp and gyn for further review.
Surgical menopause. After hysterectomy, you are probably in a lower hormone phase, possible low levels of vitamins, and may have low grade inflammation that can cause fatigue. If you have seen your pcp/gyne and have not had much success, see an integrative physician that can use bhrt and lifestyle to help.
Ovaries +/- Uterus. Hysterectomy can result years later in loss of estrogen from the ovaries and sleep disturbance with or without menopausal hot flashes. Loss of red cells, depression as well as sleep loss can cause fatigue. Low iron, insomnia, and low estrogen at ages less than 60 could be your problem.