Hi Joavila. You got some good suggestions in response to your prior post. You need to push yourself to handle this in a constructive way, even if it is hard to do. You cannnot reverse what happened, and wishing that you could do so won't change that. What happened, happened.
Most likely, nothing will come of this. Even if it does, stealing less than $20 from a store is a minor crime. If you were accused of this, you would presumably admit what you did, apologize for it, take whatever fine or other punishment you might receive, and move on with your life -- having learned a lesson.
It will not ruin your life. It will not preclude you from continuing your education, getting a job, having a family, doing some good for your community, etc.
Right now, you are punishing yourself much more than the legal system woud punish you. Why?