The Warriors are now seven points adrift of Northampton, who host the Cherry and Whites next weekend.
Brain said: "I can't remember the last time we got a break in a game, but I'm not blaming luck on our predicament. We've lost too many games.
"There are no bad teams in this league, but we are clearly the worst - the table doesn't lie.
"What is worrying for me is that Gloucester have to go to Northampton next week and, if they play like that up there, they'll lose.
"If we play like we played today against Bath, we can beat them. We've got six games left and we've got to win two points more than Northampton to stay up."
Worcester started brightly and showed more incision going forward, but were made to paid for their indiscipline by Gloucester.
Peter Buxton and Mark Foster snatched opportunist tries for the home side and James Bailey crossed when Worcester were chasing the game.
Ryan Lamb slotted 10 points and his replacement, Ludovic Mercier, added another eight.
Worcester's only touchdown came from Lee Best, shortly after the full-back had a dislocated thumb put back. James Brown kicked a drop-goal, three penalties and his only conversion.
"I can't remember ever losing a game when the opposition attack didn't trouble us at all and we gave quite a lot of trouble to their defence," Brain added.
"Yet, we lost the game by 14 points and that's hard to take."
Brain's view was echoed by Gloucester counterpart Dean Ryan, who was wholly dissatisfied with his team's display in front of a sell-out crowd at Kingsholm, despite the win restoring them to third place in the Premiership.
"I'm disappointed," Ryan said.
"That was one of our poorest performances of late and I'm not happy about that.
"We've got some problems with injuries, but back that up with a poor performance and Worcester should be going home very disappointed not to be in the mix.
"They missed a gilt-edged opportunity to get a win here."