Are you in the US? What state are you in? if you are in the states call 211 for local resources.
To find the best resource the fastest I would walk into a local Suboxone or Methadone clinic and just tell them you need help getting into rehab. Regardless of whether your DOC is opiates or if you’re a patient with them or not they should be able to refer you to someone who can help, or the right direction to go in. A hospital ER will also do. I know you are scared but you need them to direct you to a caseworker who knows the ins and outs of your location/state insurance/funding. Both places can direct you to a social worker.