I claim the ornamental design for a combination bed sheet and pillowcase, as shown and described.
FIG. 1 is a top view of the combination bed sheet and pillowcase.
FIG. 2 is a bottom view of the claimed design.
FIG. 3 is a right side view of the claimed design.
FIG. 4 is a left side view of the claimed design.
FIG. 5 is a front view of the claimed design.
FIG. 6 is a rear view of the claimed design; and,
FIG. 7 is a perspective view of the claimed design.
The long dash broken lines in FIG. 7 represent environmental subject matter showing claim in use and form not part of the claim. The short dot-dot broken lines represent claimed stitching.