College Students Hospitalized, Shocking Pic Shows Them Passed Out on Cancun Bar

College student Zara Hull is speaking out after she and her friend were apparently drugged at a swim-up bar in Cancun, Mexico ... sharing the harrowing details that landed them in the hospital.

Hull, who spoke with CBS News after the incident, recalled having a swim day at a Cancun resort with her boyfriend, Jake Snider, and pal Kaylie Pitze. What started out as a fun day in the sun quickly turned disastrous ... as 2 minutes after ordering water at the bar, the women found themselves feeling incapacitated.

A troubling pic of the scene is making the rounds online, showing Zara and Kaylie holding hands as their heads slump on the bar top.

Zara said ... "When I tell you, I have never felt like that in my life. I was so heavy to the point where I could not lift up my head or anything."

Zara and Kaylie were rushed to a local hospital last Thursday after ZH began suffering seizures -- and she says it got so bad, she was heavily sedated and put on a ventilator.

The college student said the hospital demanded at least $10K just to treat her ... and has accused the hospital of holding her "captive" while demanding a big payout. She did not name the medical institution out of fear for her safety.

Zara was later moved to a hospital in Dallas, where she has remained since Saturday.

The aftermath of the ordeal has been traumatizing for Zara, who said she's suffered around 18 convulsions, and had her lungs fail repeatedly. She has since started physical therapy to learn how to walk again after the medical crisis.

Her bottom line was clear ... "They say, 'the resort is the safest place' ... that’s not true."