Yup, something has changed. Without anything to compare or refer back to, it is very hard to make assumptions. If at all possible, another good idea, although very tedious for some, is to maintain a practice log with notes to refer back to. Log what is working for you as well as what is not.
For example yesterday during practice I was noticing flyers to the left on occasion. I couldn't figure it out for the life of me. I went back to the logs and notes and found the that same thing happened in the past and the culprit was that the string was making slight contact on my chest. The real problem was that I was shooting off my heals, the string contact was just the result of the problem, when I adjusted that, the problem vanished. But without my notes, I would have had to reinvent the wheel or make the discovery over again which could have been timely.