I agree with daddus... keep your head up. It's hard to pattern deer in the woods. Many times the trail you may have your camera over may be a trail they don't use anymore. I have had that problem before. Keep looking for new fresh signs of movement. One thing I do on a trail to see if it's a trail still in use is I find a thick branch or limb off a tree and somewhere on the trail I'll brush the leaves away with my foot and then press the dirt down with my boot and then take the limb and slide it over the spot to sort of "level it off". Make the dirt smooth and flat. Then check it in about 2 weeks for tracks. Now, this typically works best when the dirt is some-what moist from rain or from being under the leaves. Also- it works best in the woods rather than along fields or wood-lines.
...and on that day when my strength is failing, the end draws near and my times has come, still my soul will sing Your praise unending, ten thousand years and then forevermore!