Dear Patient, good evening.
The symptoms which you have mentioned can be related to lot of illnesses, but to tell you they can be generally present.
As with the symptoms there is lot of unanswered questions your age, your sex, your stature, weight, height ,as it will help in the diagnosis and treatment.
if there is general weakness,
fatigue and poor memory can be related your lifestyle, dietary habits and biggest factor now a days is
stress.
Try some muti-vitamin supplements and increase the water intake,seasonal fruits, green leafy vegetables and workout/walk daily.
If you want any other advice please feel free to ask.