I've been finding the same thing happening to me. Two days ago I had a major increase in back pain, leg pain starting, foot pain - enough to really frighten and depress me. Thinking perhaps I had pushed myself way too far, I spent almost all the next day in bed, and that seems to have taken care of it.
However, it really is starting to make me worry about returning to work on the 15th. Once I'm back, that's it - all disability cuts out and most of my sick and vacation time for the year is already taken. I can re-apply for disability but I need to wait 30 days if it's for the same issue. As a neigrabroador asked me, "Can you do it? Can you do it every day?"
So, MOM is right...3 steps forward, 1 step back.