From the past few days, I am feeling tired. Normally I enjoyed any task, which is given to me at my workplace. The sudden feeling of tiredness raised alarm in my mind. It made me think whether it's the physical work/mental work /or the work that I don't like made me feel so?

I think third case is applicable to me. Currently, I am busy in the preparation of a big document. Daily I have to do tough mental exercise to complete that work within stipulated period of time.

I believe that it's the interest in your work determines your tiredness level. You never feel tired if you read a big novel if reading is your hobby. But reading course books may make you feel tired. When I was a child, daily I gave new explanations to my mom to avoid studies because it makes me feel exhausted. But gardening or travelling never makes me feel tired because these are my hobbies.

Feeling tired is nothing but a mind generated thought. When we are doing things of our interest, our energy level automatically increases and whenever we have to do something that we don't like, our mind makes us feel tired.