What do you recommend if i had thyroid cancer thyroid removed how long will meth be detectable in my system is it possible to test positive 6 mo after use?

I don't know what: having a thyroid cancer removed would have to do with your methamphetamine problem, but I don't think they are related, and one has nothing to do with the other. Methamphetamine is rapidly metabolized and excreted, and usually drug tests are negative 3-5 days after last use. It cannot be positive in urine 6 months later, but hair testing can detect it for that long or longer, depending on length.