CHICAGO (CBS) — Two Southwest Airlines flight attendants were sent to the hospital, after a flight from Boston to Chicago was forced to turn around due to serious turbulence.

Southwest Airlines flight 147 left Logan International Airport around 11 p.m. Eastern, and less than an hour later, began experiencing strong turbulence.

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Several people became ill or fell on the plane when it started to shake.

“They thought one of the flight attendants might be having a seizure. His eyes were glossed over, and he looked like he was going to pass out,” passenger Sherry Sanchez said. “At that time, there was three or four other people that were throwing up; and another flight attendant, because of the turbulence, had fallen – I think into a seat or something – hurt his arm, and he had a swollen arm.”

The plane turned around to return to Boston, and two flight attendants were taken to the hospital to be treated for injuries.

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No passengers needed to go to the hospital, but many were definitely rattled.

“I felt the pressure in my chair and it was pretty crazy,” passenger Nick Piker said of the turbulence. “It left me a little disoriented just sitting in my chair, and then immediately after I heard the flight attendant say they needed medical help in the back.”

After the plane returned to Boston, a new flight crew was brought in to resume the flight to Chicago. The flight arrived at Midway International Airport about 4 ½ hours late.

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Piker said passengers were just glad everyone was okay, and there were no serious problems.