Lack of energy

Hi am 24 and was dignosed with endometriosis over 3 years ago got it removed nearly 2 years ago and did not suffer from any symptoms. Since last july i have been in server pain whr was taking at a&e in november. Just feel worest as iv got no energy and body feels shaky epecially from my hips and legs and bad backach gp will not prescribe any strong painkillers currently taking cocodamol you can buy over counter not sure what else to do.