It happens. Sometimes it's a "false positive", sometimes it's something else totally innocuous that mimics a drug. I know that they told me not to have anything with poppy seeds before a urine test (think poppy seed on a bagel or a bun!) because it could lead to a positive for morphine, codeine or other opiates. Once I tested positive for opiates and I never "used" them except as administered when I was in the ER for alcohol--and that had happened 6-months prior. Some mouthwashes can lead to undue alcohol readings. If you're around people who smoke pot the smoke can actually settle on you enough to cause a positive. I would explore this with the people who gave you your test. They have probably run into it a lot. Or talk to a doctor, or google the info. And congratulations on the 668 days! You're doin' great!