I've never been interested in "proving". Still, there have been long dry spells where I find (see, hear, etc) no evidence and doubts about my own remembrance creeps in thus I think I know what you're talking about. For me, that has not lasted yet. Each time it ends with an incredible slap upside the head which removes every hint of doubt. You might not realize it from the amount of time I spend here, but I really don't obsess over bigfoot, I don't spend any more time here on this forum than I do on others for other interests .. hunting, fishing, backpacking, etc. Sometimes I wish I had not seen what I've seen but since i have, I have. My capacity for deliberate self-deception just isn't great enough to let me pretend otherwise. It would be simpler if I could. I don't deliberately bigfoot very much, it's usually secondary, or at least equal to, some other concurrent activity ... same time, same location. I can't put bigfooting behind me without also giving up the other things I enjoy ... and I just won't.
Sometimes there's nothing to do but get back on Rocinante and head of fin search of another windmill.
MIB