Demi Lovato may have OD'd on drugs laced with fentanyl

*According to TMZ's source, after leaving a party at Saddle Ranch at 4AM, Demi texted her drug dealer to come to her house.

*When he arrived, the two freebased Oxycodone on some tin foil.

*The source says Demi, who had been buying from the dealer since April, was unaware that he had a habit of buying drugs from Mexico that were laced with fentanyl.

*After noticing Demi was breathing heavily while lying in bed, the drug dealer peaced out without telling anyone Demi might be in distress.

*One of her staff members found her unconscious about 7 hours later and administered the Narcan and called 911.