Quote - I am getting annoyed with my constant feeling of sleepiness or tiredness when I am working on poser making it hard to focus and slows down my production. There are times I need to blink when my eyes are getting watery.

I sleep early like 11-12 at night or earlier and wake up 7 am. I don't drink coffee. I eat alot of grains and healthy food.
What's missing? Do i need some exercise or something? How do you cope up with this?

Sounds to me like you need to get your eyes examined.  What you describe sounds like an eye related issue.  

"It is good to see ourselves as others see us. Try as we may, we are never
able to know ourselves fully as we are, especially the evil side of us.
This we can do only if we are not angry with our critics but will take in good
heart whatever they might have to say." - Ghandi