The most important thing during illness is to offer to God patience and thanksgiving for His merciful visitations. Sickness purifies sins and gives one time to meditate on the past.
In answer to your question as to what constitutes a happy life, whether splendor, fame and wealth, or a quiet, peaceful, family life, I will say that I agree with the latter, but will add the following: A life lived in humility and with an irreproachable conscience brings peace, tranquility, and true happiness. But wealth, honor, glory and exalted position often serve as the cause of a multitude of sins, and such happiness is not one on which to rely.
When God, using our conscience, calls us to righteousness and yet our self-will opposes Him, He respects our freedom and lets our own will be done; but then, alas, our minds grow dull, our will slack, and we commit iniquities without number. On the other hand, the fruits of the spirit are soon granted to them who follow the commandments of Christ our Lord.
A life lived in the world can be as good, in the eyes of God, as one spent in a monastery. It is indeed only the keeping of God's commandments, love of all, and a true sense of humility that matter, wherever we are.
Remember always that, once we have decided consciously to strive after righteousness, we cannot escape catastrophes and sorrows, no matter where we are.
God smiles on the compassionate heart. Every time a beggar knocks at your door, try to perceive Christ Himself under the humble disguise. Would you, under any circumstances, let Christ knock in vain? The moral qualities of the individual beggar have nothing to do with it; that is Christ's concern, not yours. Who are you to judge your brother? Christ is using the beggar’s hand and mouth to test your compassion of Himself. Will you fail Him?
You are, I am sure, aware that for you penitence is now no longer limited to disclosing your sins to your confessor, but that you must now bear your sins in mind always, until your heart nearly breaks with their ugly load; and would break, were it not for your firm faith in the mercy of our Lord.
Pray before your body takes rest on your bed... If you are tempted, make the Sign (of the Cross) on your forehead reverently… for this is a known and tested weapon against the Devil.
You ask for some way of completely eradicating irritability. The inclination to irritability is given us to use against sin, and we were never meant to use it against our fellow men. When we do, we act contrary to our true nature.
You describe how bitterly you regret the inefficacy of your prayers. Beware: to wish for consolation or revelation in prayer is a sure sign of pride. Pray humbly, in perfect simplicity, seeking salvation only through forgiveness, & having faith that God will extend to you His mercy - as He did to the publican.
The kingdom of God is always present for him who desires and wills it. When a man's disposition and way of life are like that of an angel, most assuredly this is the kingdom of God. For God indeed is said to rule as King when nothing worldly meddles in the governing of our souls and when in every respect we live not of this world. This manner of life we have within us, that is to say, we have it within us when we desire and will it. We do not need to wait a long time, or until our departure from this life; instead, faith and a God-pleasing life which accompanies faith are very near us.