Bushell was defending his Olympic title in Rio, but managed just a sixth-place finish at the Olympic Stadium having crossed the line in 15.09s.
The 26-year-old does not expect much better in the 400m event, which begins on Saturday, and admitted that it had been a "difficult" Games for him so far.
"I'm a little disappointed but if the weaknesses [are] down, we can work on them," he said.
"I always come to medal, that was always the sort of dream if you like. It didn't happen today and we'll work on it in the future. 400m is always my sort of bogey event, so I'm just going to go there, enjoy myself and see what happens really.
"It's a tough one. It's been a tough Games so far and I've been... it's just tough being out here but we make of it what it is. It's very different, every Games are different. That's it really. You've got to adapt to each country really."
Bushell also won a silver at the Beijing Olympics.