Answer
In the Name of Allah, Most Gracious, Most Merciful.
All praise and thanks are due to Allah, and peace and blessings be upon His Messenger.
Responding to your question, Sheikh Ahmad Kutty, a senior lecturer and Islamic scholar at the Islamic Institute of Toronto, Ontario, Canada, states:
While you should not give up praying to Allah to cure you of your affliction and inspire you with confidence, there is no need for you to be depressed over this challenge you are facing. Everyone in life faces tests and trials; that is part of life.
The Prophet (peace be upon him) taught us that the prophets are the ones who suffered the worst kind of tests and trials, and yet they never protested against the will of Allah. Instead, they took them as challenges for spiritual growth.
Indeed, they tried their best to prevent what they could, while leaving the rest to Allah; our faith teaches us to accept the inevitable as part of the will and find peace in resignation to the divine will.
You should arm yourself with dhikr and duaas: Read Al-Fatihah, and the last three surahs of the Quran and the following Duaas:
Allaahumma innee a’oodhu bika mimmaaa ajidu wa uhaadhiru
(0 Allah, I seek refuge in You from the pain and affliction I experience and fear)
As’alu Allaaha al-azheem rabba al-‘arshi al-azheem an yashfiyanee
(I ask Allah, the Lord of the Mighty Throne, to cure and heal me from all afflictions).
I would also advise you to ask your physician to refer you to a specialist who can help you overcome this feeling of lack of confidence; for I am afraid, if you are not able to control it, you may fall into depression.
I pray to Allah to cure you of your affliction and give you confidence to face the challenges you face.
Almighty Allah knows best.