Newcommer, I’m sorry to hear about that, and I hope you feel completely better very soon!
Emunah could be the solution, depending on what the problem is. But overall Popa is right.
Have you tried to figure out what the problem is? Sometimes it’s not immediately obvious.
For example, are you getting plenty of sleep and exercise and social interaction? Today’s isolated, sleep-deprived, sedentary lifestyle is not natural. It causes many physical and psychological problems.
Do you take time to help others and thank G-d for all the good in your life? Focusing on the positive and on others makes people feel good, and takes people’s minds away from themselves and their problems.
I’ll point you to a couple seforim I enjoy in case they are of help to you.
Google the following sentence and you will find a chapter of a chassidic sefer (Likutei Eitzos) about happiness: “Search for your good points in order to make yourself happy.”
Search for this phrase and you will find another, briefer chapter on the same topic: “It is hard for him to calm and settle his mind.”
Anyway, hatzlacha!