I always feel the need to tell people everything

Sorry to hear of your situation.

Possibly you are overlooking that your own Self is someone worth talking to as well.

None of us are ever really alone because we are always with ourselves.

Self-talk is a major part of what guides our decisions and how we make sense of relationships and situations.    Even after telling people the stories or activities, hearing their comments, it is always within ourselves that we decide if the way we were received by these others, the comments we heard back, feel right and accurate to our lives.

I hope the feeling of a hole in your stomach would decrease by enjoying your Self.    I am guessing that hurting yourself makes the stomach hole feel less bad because the physical pain you create in yourself distracts you from feeling it.

Enjoying your Self by talking kindly, loving, and having inner dialogue may very well decrease the feeling of a hole, altogether.

Sending lots of good luck!