After being arrested for DUI last week, Olympic swimming champion Michael Phelps announced he was going into rehab this morning. He Tweeted, “I’m going to take some time away to attend a program that will provide the help I need to better understand myself.”

Phelps, 29, was “speeding excessively and crossing double lane lines within the Fort McHenry Tunnel on Interstate 95 in Baltimore around 1:40 a.m. Tuesday,” according to Maryland police. He was found to be going 84 mph in a 45-mph zone and his blood alcohol was reportedly “nearly twice the legal limit.”

Phelps, who was arrested for DUI in 2004, apologized for the incident later that day. TMZ later reported that Phelps had been on an “8-hour gambling binge” at a Baltimore casino before his arrest.

Today, he Tweeted his disappointment and a desire to work on himself:

Phelps is the most decorated Olympian in history; he has 22 medals, including 18 gold medals.