I’m an undergraduate student, and I find that multiple times (each week), I have an obsessive need to make sure something I’m doing is allowed/accepted. I do this by asking the TA/Professor for my course in question. 
It’s usually situations where it’s *almost* certain that something I’m doing is ethical, but I feel the need to ask for each instance if the professor did not explicitly state the rules.
Some examples:

* A little while back I asked my professor if thesauruses were allowed, and if I had to cite them. Based on common sense, I was over 95% sure it was fine – even on the university library website, links were given to a few online thesauruses. When I asked my prof, he said that it was absolutely fine, and that thesauruses did not have to be cited.
* My professor for another course mentioned that certain calculators were not allowed on tests (the kind of calculator I currently have). I wondered if I could still use my calculator on assignments, and I assumed I probably could since he only mentioned tests. I asked the TA about it, and he said I could.
* I was wondering if I could use my course notes while doing an assignment. I was always allowed to do this in high school, and I was 99 % certain it would be okay. I asked the TA about it, and he replied that it’s completely okay.

I want to earn a degree that was done in perfect ethical standing. I feel that if I don’t ensure every single thing I’m doing is completely ethical, then inevitably a few of my actions will be unethical over the four years.

I don’t want to have to keep pestering my professors about every single detail, as it wears on me and also (I’m sure) will wear on them. At the same time, I have the problem I discussed above. Should I just accept that it's pretty much impossible for anyone to finish a degree with a 100% ethical standing? Any advice/experience would be greatly appreciated.