thats turkey hunting; I have had the same thing happen to me on occasions.
this year,I knew where a gobbler was roosted.I walked 1/2 mile so as truck noise would not spook the bird.I was with in 75 yards 45 min. before any sign of lite.
when the crows started to call,I gave a soft ;very soft tree yelp,the gobbler took flight and flew 1/2 mile to a big clear cut. go figure!!!!!
there had been a lot of pressure in the area I was hunting,so someone may have spooked him real good.who knows??

" thats why they call it hunting;not shooting." just give it another try,and another try.
good luck.