we do these two things as a result of physiological responses rather then emotional ones.
More so, these can be triggered by emotions, or trigger emotions themselves.
Some people do eat because of an emotion, but this is mainly the feeling of happiness and safety rather than fear. This is also why it is easy to start eating too much, but very hard to stop again, since you get somewhat addicted to the relaxed happy feeling the food gives you.
Personally I have a very hard time sleeping if I fear something. Especially if it was even remotely related to sleeping. Fear makes you tense us and get very awake, which is really bad when you want to go to sleep, ask anyone stressed because of exam papers or having seen a horror movie of the good kind.
Rather, a nice cozy and warm bed will make you relax and sleep easier, even if you are not actually sleep deprived.
As for school work, it seems that would only go for people who does not do what they really want to. I am trying to get an educations so that I can do what I love for the rest of my life. This does take hard work, and some stress that I might not be good enough, but even if I had to live off nothing because of the education I have chosen, I would still work hard to learn and become better at my field, because I love doing it.
Really, I generally get really stressed and worried about my assignments and papers, and this often STOPS me from actually doing the work I need done, which is really counteractive.
And again, first of all, boredom is healthy to some degree. You really do need those moments where you have nothing to do, because that will kick start some kind of inspiration, motivation or action to make you stop getting bored. Or simply get yourself to do something else, more important.
Second, most people will do something they enjoy, or something they need to do, not because they don't want to be bored, but because they enjoy it or need to do it. Sure, boredom can kick you to do your homework, because you have nothing else to do, but I doubt it is the fear of it as much as boredom being really, really boring to deal with.
And just to get back to the horror movies: We watch them to get frightened, and get that jolt of adrenaline. We actually enjoy fear.