The Baggies led the game 2-0 early on, before the visitors hit back to level the contest after 73 minutes.
"That's probably the hardest Albion game I've had to deal with, everyone in the changing room is very disappointed," the Scottish international told the club's official website following the game.
"It feels like we've just lost the game, we had three points in our hands and we gave it away so late. It's very disappointing. We spoke before the game about a good early start and I think we did that very well, obviously the first half an hour to 45 minutes was probably the best we've played all season.
"We got two goals in front and we should really be seeing the game out from there and that's why it feels like defeat at the minute. We've got to stick together now, we've got a big game next weekend at Norwich and Monday we start work on that."
The draw leaves Cardiff in the Premier League relegation zone, three points adrift of West Brom, who are in 17th position.