When you started up again were you squatting 3 days a week? You may be generating too much stress too quickly. 285 is reasonably close to 315, so a light day and 5lb jumps may be in order. Also, what was your programming like when you hit 315, was that in a NLP? If not, you would likely not be able to NLP up to that number and a programming modification would be needed before then.