Newcastle looked to have kicked their season into life with three successive wins at St James' Park but slumped to a dismal 3-1 defeat at West Ham on Sunday.
The Hammers hadn't won at home since February prior to Newcastle's visit and the Magpies are now winless on their travels since April.
Jacob Murphy put Newcastle into an early lead at the London Stadium but West Ham deservedly levelled through Lucas Paqueta and then got themselves in front deep in first half stoppage time when Sven Botman turned into his own net.
Howe responded by making three changes at the break - with star forwards Anthony Gordon and Nick Woltemade both replaced.
And such was the head coach's disappointment at what he'd seen in the opening period, he said those who stayed on the pitch were lucky not to be hooked.
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"That was the frustrating thing about the first half, I almost could have taken anyone off and I think that was a reflection of where we were in that moment in the game," said Howe.
"It's very rare for me to feel like that. In fact, I don't think I have since I've been manager at Newcastle.
"I felt the team needed some shaking up at half-time, that's why I did what I did.
"I was really disappointed with the first half. We started well, scored early and you think we can really grab hold of the game from that moment but we didn't, we let it slip away and the longer that half went on, the more frustrated I was with our performance.
"We were unrecognisable in certain aspects of our game. I made the changes to try and bring some energy and different dynamic and feeling to the team.
"I thought we were better in the second half but weren't particularly great."
Newcastle rarely looked like finding a way back into the game and substitute Tomas Soucek wrapped up the win for the hosts deep in stoppage time at the end of the game.
And Howe didn't hold back in the dressing room at full-time.
He said: "I'm always very honest with the players. I believe in honesty whether that's positive or negative.
"I was very honest. I always try to be fair. Now the key thing will be everyone's reaction."