Sonam, it depends on what you mean by "low energy". Feeling easily drained could be a sign of a serious condition. May I ask you: have your sleep patterns changed since this drained feeling began? Do you have trouble picking yourself up out of bed in the morning? Have you been under chronic stress for a long period of time, or experienced some sort of trauma (car accident, loss of a loved one, victim of crime), or perhaps a move or job change in addition to chronic stress?
When the body becomes overwhelmed by stress and chronic fatigue sets in, it could be that the adrenal glands are becoming depleted. This is a potentially serious condition that TM has no solution for, I can tell you from experience. If you think this may be your problem, PM me, and we can discuss it further. There's a simple remedy, if it is, in fact, adrenal fatigue that you're experiencing.