Developing Your Psi Energy.., Should it start off this tiring? Options

I've been running the regular meditation and practices for developing your psi energy as described on some sites shown here. Visualising a sphere behind my abdomen, pulling the energy up through my chest, and to my hands, ect. But what I have noticed recently is being completely exhausted the day after. I've been keeping a routine of 30 mins on day, none the next, and repeat. Today I could barely lift my backpack. I haven't been doing much out of the ordinary other than extending my time from 10 to 30 mins. Perhaps I'm rushing it abit? I'm just curious to know if anyone else has had these effects on them.

For a newcomer, it is normal to feel tired. This is the first time a person is using mind power to perform energy manipulation. The theory is similar to someone who does a kind of sports for the first time. As times goes by , the tiredness will fade away.