I am at a Loss
There is a sort of pain associated with loss -- loss of a valuable possession, money, etc., can cause a "pang" of pain. Similarly, making a mistake can cause this feeling. The two feelings are nearly identical.
Related is the painful feeling of fear of such events, the fear of such pain. I fear leaving my camera on the front seat of my car. I fear certain types of groups such as parties.
Memories can trigger these painful feelings, memories of past painful events. Thinking can trigger these painful feelings, thinking that you might make a mistake.
These things can turn into a cycle that interferes with life when one wants to do something, and upon thinking of the doing of it one is hit by this painful feeling that one might make a mistake, which then gets reinforced by the memory of an event which resulted in a painful feeling...
The bigger problem is when the painful feeling comes with seemingly no reason, no associated event, the pain just comes.
A person walks into the room and you are in pain.
A dog barks in the distance and you are in pain.
There is a vague smell and you are in pain.
An automobile slows nearby and you are in pain.
There is a look on a person's face -- even on a trusted friend -- and you are in pain.
You are in pain and there is no reason. You are in pain and there is no one to talk to. You are in pain and there is no way out.