The 30-year-old Londoner has been forced to pull out of his latest comeback bout with an arm injury, the latest in a long line of problems.
Barker's career has been dogged by injury and inactivity, not least a long-standing hip problem which he has finally overcome.
He had been due to fight for the first time this year against Simone Rotolo at the Alexandra Palace on September 8 before suffering a bicep injury in sparring.
"It was unfortunate, I was in the gym sparring and I caught my elbow on my sparring partner's elbow and damaged the tendon in the bicep so we had a scan and the doctor ruled me out," said Barker (23-1 14KOs).
"I feel like I've run over a cat! Stepping over drains, walking under ladders, I don't know what's going on. Funnily enough I've been avoiding all those superstitious things and I'm not normally superstitious but I was so desperate for nothing to go wrong for that fight."
Barker revealed he even feels like walking away from the sport.
"I'm really down at the moment and struggling to stay positive," he said. "I've got to try to keep my head up. I'm a young 30 so if I do choose to carry on then I'm sure my body can do it.
"It's a tough question for me at the moment when I'm this low and this down.
"I'm so down in the dumps because the most valuable thing on the planet is time and I've invested so much into this fight. It was the perfect comeback fight, a good opponent at a local venue, everything was bang on and for it to fall through has completely shattered me.
"I'm bitterly disappointed.
"So these kind of questions and doubts do start creeping into your mind."
Barker lost a valiant world title challenge against middleweight king Sergio Martinez last year and says it has been frustrating to have been sidelined since.
"In the Martinez fight I proved I belong at that level and all I wanted to do was build on that momentum by getting fights under my belt after all the hip injuries," he said.
"That's the most frustrating thing for me.
"There are big fights out there and I'm lucky that I'm part of such a booming division internationally and domestically.
"Martin Murray and Matthew Macklin are out there and they are big fights which would get me up for a ring return.
"I think I'm just being negative at the minute because I'm down and I'm sure I'll bounce back stronger than ever."