Welcome
You're in a good place here, so it's great that you're posting and reaching out :-)
With your AA sponsor, it's really hard talking about a relapse, but I admitted it to my sponsor a few times and she would tell me to pick myself up and start again. We'd then have a long conversation about what to do differently this time and start over on step one.
Being honest has been a huge part of my sobriety, it's scary though!
Have you tried looking into getting some extra help aside from AA? I go to a drug and alcohol community centre once a week and they provide therapy etc.