The authorities can do whatever they want. Here it sounds like they believe they have sufficient evidence to believe a crime was committed and you were the one who committed it. You have mitigating factors. You need a qualified, good, aggressive lawyer to represent you and advocate for you to get your circumstances across to the prosecutor, assuming given other facts, that is advisable. Consult an attorney directly.
I'm a little unclear - if there was a quantity of meth and a baggie, and whether or not they were together. If they were together or there was just a baggie, but you did not "knowingly" possess the drug or have the intent to store or conceal drugs in the baggie, then you are not guilty. Proving that is a different matter. If it's important to you, hire a lawyer and fight the case.
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If the amount of drug was sufficient to test then you could be charged with a dangerous drug offense. If the drug was contained in the baggie then you could be charged with possessing the baggie as drug paraphernalia. You should consult with a criminal defense lawyer for their advice.