They were vanquished 48-6 at Hull FC and have now won just once in their last nine games.
Troubled Castleford were 24-0 down inside 24 minutes and never looked capable of recovering.
Powell said: “It was a tough game.
“Obviously the start rattled us. We were 12 nil down in no time and we couldn’t really find a way back in. Kick tries were damaging us all the way through and it’s disappointing; we’re in a real tough situation.
“We have to find a way out of it and we are short of confidence.
“We can’t get that through training as we play Thursday, Monday and Friday.
“We need a win to get that confidence and I just have to make sure they’re getting the right messages from me.
“We have to keep our resolve. We have a lot working hard but too many just not playing well at the moment.”
Castleford’s young wingers Brad Day - on his Super League debut - and Alex Sanderson were put under immense pressure by the kicking game of Jake Connor and Marc Sneyd.
“There’s no blame attached to the young fellas,” insisted Powell.
“Hull have some outstanding players on those edges and they caused us a lot of trouble.
“We worked hard but they were too strong and we’re not playing with confidence that’s clear. We have some players who desperately need to find some improvements in their game.”
Powell praised the rugged prop Tyla Hepi and said: “I thought he was a stand-out today; defensively he really went after the opposition.
“He’s one of those players who get under the skin of opposition; they want to go belt him as he keeps coming at you.
“Jacques O’Neill went well when he went to nine and Adam Milner was great today.
“As professional rugby league players, no one wants to lose. It’s happening to me and this team more than I’ve ever experienced but I’d just ask everyone to realise we’re working hard. Clearly that game against Hull KR on Thursday is really important.”
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