Barker spoke about the emotional toll the 9-8 defeat to Oracle Team USA has taken on himself, manager Grant Dalton and the rest of the team.
"It's like the body just suddenly goes into shutdown and all the emotion, the nerves, the tension ... dealing with it is just one of the hardest things.
"It's tough. You're trying to gather yourself after everything that's happened and the vultures are already circling."
He said he would cherish another opportunity to work with the team, but decisions about its future had to be made soon.
"We're in a process or a stage now where decisions have to be made to allow the team to continue because we have already had guys targeted by other teams ... if we start losing people now it won't have the ability to carry on."
On the prospect of Sir Russell Coutts returning to the team, Barker said: "I haven't spoken to him so I am not really sure what his plans are but I would say it is very unlikely."
He also described feeling "powerless" against Oracle's boat, but said his team sailed their best in the last race.
"There wasn't a moment in that race where you said 'oh we wish we had done that differently' or 'we could have done this better', we did what we set out to try and achieve and, again, to just watch them sail past us upwind was not an easy thing to deal with."