The ornamental design for a sleepingpillow, as shown and described.
FIG. 1 is a perspective view of the sleeping pillow showing my new design;
FIG. 2 is a front view thereof;
FIG. 3 is a back view thereof;
FIG. 4 is a right side view thereof;
FIG. 5 is a left side view thereof;
FIG. 6 is a top plan view thereof; and,
FIG. 7 is bottom plan view thereof.
The broken lines shown in the drawings illustrate portions of the sleeping pillow that form no part of the claimed design. The surface shading illustrated in the drawings is provided merely to highlight the contour of the design; it is not intended to be illustrative of texture or gloss.