After cesarean hysterectomy and prolonged it has taken me months, and I still cannot stand long. What went wrong?

Probably nothing. A cesarean hysterectomy is major surgery. Some docs only perform this a handful of times during their career. The procedure implies that you completed a pregnancy, probably had a complication such as heavy bleeding and needed a life saving emergency surgery. It takes time to recover from each of these let alone all together.It may take months for your stamina to return. Follow up with the surgeon.