I need energy, and i feel tired all the time. what can i do?

Feeling tired: I would make sure you're eating a healthy diet and getting at least 7 hours of sleep nightly. If despite these measures you still feel tired all the time, I'd get a checkup with your doctor to elucidate the cause of your chronic fatigue.

Weakness: multiple causes can result in weakness have your primary physician do a complete metabolic workup that should also include thyroid function tests; also maintain good sleep habits, proper nutrition, increased exercise, yoga.