Window A

sensitivity is a curse really. if an apparatus is highly sensitive, it tends to have a tradeoff with its working range. you see things in minutiae, sure, but the minutiae is all you can see. there is no larger picture, and sometimes it's like those occasional contests they have in magazines where they show a photo in high magnification and you have to guess what the object is, and all there is to go by, is perhaps a tiny distinguishing feature that seems somewhat distorted by how much larger it is than you're used to.

sometimes there's the sinking feeling in your tummy. that means you're either ill or you're about to be violently ill. or sometimes it means you're about to cry, really. so it depends.
look at what's happened before the sinking-feeling incident --- did you eat something raw/nearly decomposed/weird? did you just see something that is out of your comfort zone? or do you just feel depressed because you looked into someone's eyes and for some unfathomable reason, you sensed contempt/disdain/dislike/irritation?
find out the cause, and apply a suitable remedy. sometimes, a hiatus from everything is a good solution. like a trip to thailand for retail therapy. that is highly recommended. unless of course, you have 2 years work to memorise in 8 weeks. in that case, find a large tank. throw said two years work into tank. stock with sufficient food, water and vitamins and jump in. charge for admission. at least if all else fails, that's money in the pocket.