Feeling numb is an emotional protective function. It occurs as a defense against unresolved overwhelming pain. You probably reached the tipping point when you cannot hold or deal anymore with an emotional issue. If the emotional pain continued to be experienced consciously, this may lead to the unconscious perception that the nervous system would get overwhelmed and death may occur,

As you probably haven't resolved a particular issue, the pain has to be dealt with and alleviated some way. Numb is a wonderful and effective mechanism for this, though it comes at a considerable cost.

Resolution is the answer, your emotional problems have to be resolved. You may think they are to painful to achieve resolution. But there are many effective ways to release the negativity and heal any wounds.

It takes a willingness and numbness leads to loss of quality of life and is a sign to change track and get help and create a healthy and happy life for yourself, even if this seem too difficult.

As I only know what you have written in this post, I am assuming a lot and generalizing. See what fits and what doesn't.
Cheers