potty regression

CNW09

My DD has been potty trained for almost 5 months.  She is currently 26 months old.  Of course, I expect occassional accidents and have not made a big deal about any of them.  However, over the past week, she seems to have reverted back to pre-potty days (i.e nothing but accidents, wetting the bed overnight and at naptime).  My husband and I are still not making a big deal about it and have not shamed her in any way...but I am starting to worry that this could be a sign of some problem.  Also, the only major life change that she has recently is that I went back to work about 9 weeks ago and she is with grandparents all day now.  She has done great with this transition and appears to be well-adjusted to it.  Anyone have a similar experience or insight?  Thanks so much!