"It's nice to be training again. It just hit me real bad," Ljungberg said.
"I don't feel the best in the world but that's how it is. It just takes time unfortunately
"It affects people differently. (Arsenal) didn't want me to miss any games in Europe, so I've been to every professor there is to check," Ljungberg added.
"They say one percent of everyone who has migraines, they get them incredibly severe.
"This time, I won't lie when I say I probably threw up 50 times when I had it. It knocked me out. I lost my vision and the feeling in half of my body. For me it is very severe and it takes a long time to recover. There's not much I can do."