Hamilton will start from fifth on the grid after a rain-hit qualifying session, which saw Carlos Sainz record the first ever pole position of his career.
"We were fighting for the front row and all the way up into that second-to-last lap, I was (then) asked to back off and go for the last lap but it rained, so it was just a bit unfortunate," Hamilton said of qualifying.
"They (Mercedes) wanted to go for a racier power mode for the last lap and charge the battery... and as we did that, it rained a little more and the last lap was messed up."
"I was really, really hopeful because we've this incredible crowd and I was in the fight, I was feeling great," he added.
Hamilton said the car was still bouncing, particularly in the corners, but the race pace was good.
"I'm hoping we're a little bit closer on race pace compared to the last race and if we are, then if I can just hold on to them then maybe I can progress," he said of rivals Red Bull and Ferrari. "I will definitely be aggressive, don't worry."
The 37-year-old finished third in Montreal two weeks ago, only his second podium of the campaign, and he acknowledged that fifth was not a bad place to start.
"In the past race, I would have been super happy with that but because it's the British Grand Prix, you're hoping for something more," he said.