Some people get all their desires fulfilled just like that, while I struggle to get them fulfilled. How can I be happy all 7 days a week?

Consider whatever you get as a gift from Bhagavan Sri Krishna. He knows what is the best for you. Show your gratitude to Him by shower all your love on Him. He is the form of pure love. If you love Him, you can be happy every moment of your life.

Despite doing my duties regularly, chanting regularly and having great love towards God why is there some sort of emptiness in the mind. How it can be avoided and how to be ever in the happy state?

If you have great love towards God, you will not feel emptiness. True love to God and emptiness do not go together. If it seems to, then there is something wrong. Check to see which one is missing.

I have never seen happiness in my life since childhood. I get emotional when I see others suffer and I can’t bear the sight of others being sad. Why is it so?

As you have said yourself, you are emotional and not practical. That is verily the cause for your problem.

I have never been happy all my life. I need peace of my mind. I need to be happy. I need a smile from my heart. Please help me.

Happiness comes when the mind catches hold of the Divine Name without a break. That happiness is actually right within us. Have a smiling photo of Sri Krishna in your room. Whenever you are sad, chant the Mahamantra before your Krishna and pray for his grace. See everyone as children of Krishna. You will only be happy

What is real happiness?

From a small worm to the largest of creatures, every being is in quest of happiness. Have we attained it? Yes, however they are fleeting in nature. Then what is true happiness? True happiness lies within you. We need not go and search in the world to find true happiness. It lies in realizing the Self, which is your actual state of being. By merely removing ignorance this can be realized. The easiest way towards this goal is by chanting the Mahamantra.

How can I find happiness with my family members?

Don’t see your family members as mere physical forms. See the Lord in them who is making them act the way that they are. It is as simple as that.
Try to practice this, and you will start finding happiness automatically.

I am a very contented person but still, I don’t have peace of mind. Why?

This is because you are thinking that peace of mind is derived only from worldly things.