Lil Xan is Going to Rehab, I Need Help Getting Over the Hump with Opioids

[[tmz:video id="0_7lrffn1f"]] 12:50 PM PT -- Before he left for rehab Thursday, Xan came on "TMZ Live" to explain exactly why he's going, and it's interesting ... he says he's nowhere near "rock bottom." He told us he's been far more strung out on…