The Britons had come in fifth and last in their opening heat, then in the repechage on Tuesday placed third behind the United States and Japan, trailing the second boat by five seconds.
Taylor said there were a lot of tears afterwards and, perhaps castigating herself too much, said she felt she had let Copeland down.
"It was hard for me not to feel responsible in the sense that Kat is the defending champion and I don’t feel as if I’ve been able to fully back her up and help her get that title again."
"That feels like quite a heavy responsibility but at the end of the day we’re a team and we have to wear the results together," she said.
Copeland won gold at the 2012 Olympics in London with Sophie Hosking, who subsequently retired. The new partnership won European gold and world silver last year but they have struggled to find form in the run-up to the Rio Olympics.
"There's a lot of high emotion at the moment and a lot of tears. It’s just really raw emotion and disappointment," Taylor said.
Copeland was not immediately available for comment.
Taylor, who only took up rowing in 2010 when she moved to London, said the pair did not get off to a good start in Tuesday's race.
"I think I caught one of the quad strokes and we got a bit dumped. We came through 750 and I said we need to really fight for our lives here but we were never really able to close the gap."
"I definitely feel like we’ve raced better in the past. This year we’ve not properly found our gear in any of the races.
"Being right in the middle of it right now, it’s hard to see the light a little bit as to what went wrong because I feel like physically we’ve got back in shape and it feels like we should have been able to put out something more."
(Reporting by Angus MacSwan; Editing by Meredith Mazzilli)
