I’m no lawyer, but I’m guessing a lawyer’s answer to that statement would be “not necessarily”. Prohibited persons are identified under 18 U.S.C. § 922(g), and that includes anyone “who is an unlawful user of or addicted to any controlled substance (as defined in section 102 of the Controlled Substances Act, codified at 21 U.S.C. § 802)”. I’m fairly certain that opioids are controlled substances, and the law specifically says that people who are unlawful users of OR addicted to controlled substances are prohibited persons. So, from what I can see, the questions here are these:
1) Where is the legal line between lawful use and unlawful use?
2) What is the legal definition of “addicted to”?
3) How long after a person is no longer using the controlled substance are they legally no longer a user or no longer legally addicted?
All those questions require both more info from the OP (info that probably shouldn’t be shared on a public forum) and also some qualified legal analysis by a lawyer. My guess is that the OP is probably no longer a prohibited person, but that's just a guess: I’m not a lawyer.