ElJefe, it sure sounds like you did not maintain lumbar extension. It's a lot easier to maintain with your butt lower, and you see people do this a lot, kind of squatting their deadlift. Butt high is better form, but a lot easier to round your low back because of the much greater hamstring tension and pull on the pelvis.
As was suggested earlier, if you post a video, people can point out where you're going wrong.
As was suggested earlier, if you post a video, people can point out where you're going wrong.