Kasper, 20, spent three weeks battling a perfect storm of illnesses.
Mononucleosis is not an uncommon virus, and for a college student to contract a case of mono also is not unusual.
However, a Purdue University student and her family in northwest Indiana say what happened afterward was extraordinary.
Kasper hopes some workouts will rebuild her strength, because in the last six weeks, she lost 20 pounds.
"I can't believe I missed two weeks of my life," said Rebeka Kasper.
"It was a terrifying, awful ordeal for us, but was remarkable in so many ways, because there were so many wonderful people, wonderful people that helped," said Kathy Kasper, Rebeka's mother.
You cannot tell now, but Rebeka Kasper had a near-fatal combination of mononucleosis, strep C and G, and double pneumonia that resulted in multiple organ failure.
"She was as ill as any patient I've probably ever seen in my career who survived," said Dr. Matthew Meyer of Franciscan St. Margaret Health.
"She was touch and go there for a long time - we thought we were going to lose her quite a few times," said Jennifer Vanderweide, RN, of Franciscan St. Margaret Health.
Kasper's twin sister, Aly, says she literally felt her sisters pain during 21 days in intensive care.
"I could feel it - it was extremely weird - and I never want to go through it again, because it was only distress signals," said Aly Kasper.
Some people are calling Kasper's recovery miraculous. She even made it home for Christmas.
"It's just a miracle," said Vanderweide. "It is truly a Christmas miracle that she made it home when she did."
"For me, it is my miracle - like, having her OK is my miracle," said Aly Kasper.
"All these people worked so hard and so long to keep you alive. It's like - wow - so many people were pulling for me. Touching - humbling," said Rebeka Kasper.
Kasper missed the last three weeks of the semester, but her professors are letting her make up the work. She plans to return for spring semester with everyone else next month.
Kasper's mother says this was the second miracle. After an ectopic pregnancy, she was told she could not have children, but in 1991 she gave birth to the twins.