No, not worried. All bonds were down yesterday 1/2 to 1%, including treasuries, investment grade corporate, high-yield, muni's, everything. VWEHX actually went down LESS yesterday than investment grade corporates (VFICX). I don't think it's anything more than a minor correction.
Bonds seem to be going back up again today, and that may include VWEHX also. (We'll see).