Huge mistake at work

I work in a childcare centre, I made a huge mistake. A coworker left a little while ago and I was friends with this person. Now said person is making a huge deal out of what happened in this centre. Nothing serious, just little gossip about the manager. Anyway I was friends with this coworker outside of work and one night when I was drinking texted her asking how she was and such. Blah Blah Blah, at one point I sent a screenshot of the work gc about how my manager had a broken rib, in hospital, and my coworker said she saw said manager in a restaurant perfectly fine. A parent came telling me that she saw my manager as well at the same restaurant. Anyway that ex-colleague/friend sent that screenshot that I took to another coworker thats at the workplace. Now it's becoming a big ordeal and their blaming another person at the workplace that was also friends with the ex-colleague. They have nothing to do with it. I had a huge panic attack that day and left work but never admitted to sending the screenshot because I was so scared of he consequences. Now I'm planning on sending my resignation in because I'm afraid. I know I'm cowardly but I don't know how to deal with this situation. I've never had something like this happen in my entire life. I've always trusted people too easily and lived alone my entire life. How do I deal with this? Without taking a cowardly path but also not admitting to it. I told the ex-coworker to delete all their messages and such and they have but the guilt is causing me lack of sleep, I haven't eaten a full meal in two days. I haven't worked. Nothing.