Leah Messer's behavior on last night's Teen Mom 2 season six premiere was worrisome to some fans.

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Just weeks after leaving rehab, the mother of three was seen returning to MTV and facing a custody battle, as well as a divorce. Meanwhile, off-screen, fans wondered if she was "on something" during the show.

"Am I the only one noticing she is on something? She is unfocused and slurring her words. Some drug use going on," one woman alleged on Facebook. In response to the woman's comment, several fans agreed, saying things such as, "I noticed that too," "She's definitely on something," and "Poor children."

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Messer has two children from her first marriage to Corey Simms, 5-year-old twins Ali and Aleeah, and one child from her second marriage to Jeremy Calvert, 2-year-old Adaylnn.

Another fan suggested her husband, Calvert, should have stepped up and addressed the issue prior to filing for divorce, which he is seen doing on next week's episode.

"It is obvious she was on something but instead of Jeremy running to the next piece he should've been there for her if he really loved her," the Teen Mom 2 fan wrote. "Poor girl, all she ever wanted was to be loved and have a family."

While it was revealed during last night's episode that Messer is taking prescription medication for headaches, no other drug use has yet been confirmed.

For more Leah Messer, tune into Teen Mom 2 season six on Thursdays at 10 p.m. on MTV.

Tags: leah messer Jeremy Calvert Teen Mom 2 MTV Reality TV