Miley Cyrus was devastated after a severe allergic reaction landed her in the hospital, forcing her to postpone the remainder of her U.S. tour. But in a new interview with Ryan Seacrest, she also revealed how frightened she was. "It was so scary ... I had basically been poisoning myself with something I didn't know I was really scary allergic to," she said Monday. "I was on this medicine for five days and everything was all good and on the sixth day, I just woke up ... I couldn't breath and my skin -- everything -- was going insane." Cyrus suffered a reaction to Cephalexin, which she had been prescribed for the flu, and was in the hospital for nine days. "I was crying because I was so bored," she told Seacrest. "I'm laying here hooked to all these machines. Every two hours, some woman comes in and pokes me with a needle, just miserable." Cyrus revealed that she's still resting up at home, and she's feeling much better.