The Hammers won 2-0 on Saturday at Selhurst Park.
Speaking to Premier League Productions, the England international said: “Unfortunately, we created some good chances in the first half and we didn't take them. We got a sucker punch, a bit of a ricochet in the box, deflection, and then we're 1-0 down, and then we're chasing the game and get done on the counter.
“I think once you go two down, it's very difficult, but obviously you can understand why we put some pressure on them and obviously got done on the counter attack for the second, which is unfortunate. But we've just got to learn from it, put it to bed and crack on.
“It's disappointing, but like the gaffer said in there, hopefully we've just got to flip the switch and the results go in our favour and we can kick on. I think if you score when you’re on top, it's a completely different game. Unfortunately we didn't today. Hopefully we can turn it around quickly.
“As players as well, we feel like we're playing well, we're in good form, and it's just unfortunate at the moment.
“That's football, that's the way it is. Luck is sometimes with you and sometimes it's against you, and hopefully we can get on the good side of it.”