An Oregon woman developed rare blood clots after receiving Johnson & Johnson's (J&J) COVID vaccine earlier this month.

Barbara Buchanan chose J&J because it was a one-dose shot, and because experts declared the vaccine was safe after they lifted a 10-day pause, KGW8 reported. The pause in the U.S. was triggered by a Centers for Disease Control and Prevention (CDC) investigation into reports of rare blood clots.

Buchanan said she now regrets her decision. The 63-year-old first noticed symptoms six to eight days after her shot.

"I had a low-grade temperature and I just felt really tired," she said. "I thought I was suffering from seasonal allergies."

Buchanan also felt severe cramping in her legs, which she attributed to arthritis. Then she started coughing up blood. Doctors at Providence St. Vincent Medical Center ran a CT scan and discovered blood clots in her lungs, stomach, brain and throat.

"There has been an association with a very small number of people getting this vaccine that can get this special kind of blood clot with low platelets," said Dr. Ray Moreno, chief medical officer at St. Vincent.