You want to commit suicide because of health issues I really pity you for your thoughts. What a joy to have children and six year old son wow. How much naughty he would be. Enjoy your life looking at him.
No one can love your child like you do. Who will be there to fulfill your duty towards your son.
God has given you this son because he knew you'll be the best who can bring him up as a big boy.
And coming to your health issues please meet a Physiotherapist
for a knee pain
. Your pain
will come down within 5-7 days start exercising go out for walks.
If you are in Bangalore please meet would definitely help you out.