Here is a very important lesson in life that you need to keep in mind: Attending an Ivy League or “top 20” university does not matter. Keeping your stress to a manageable level and taking care of your health does matter.
I did attend two “top 20” universities (one for a bachelor’s degree, one for a master’s degree). I then spent my career working alongside people who attended more normal universities (some “top 100” and some not). I also spent most of my career working for a boss who had attended a more normal university. In the vast majority of cases, no one cares where you got your degree. They care that you get your job done. They care that you are a reasonable person to work with. They care whether you shower or bathe regularly. They do not even remember where you got your degree.
There are a lot of very good universities. There is generally a shortage of jobs for people with PhD’s in humanities. This means that a very wide range of universities can attract very strong professors.
The US puts way too much stress on high school students. Some of this comes from the pressure to try to attend a “big name” university. You should try not to fall into this trap. Relax. Do you best, but do not get stressed about minor issues such as a 3 on an AP test, or for that matter whether you get your bachelor’s degree from a “top 20” or “top 100” or “top 200” university.
Regarding not reporting an AP score, we did have a bit of experience with this. One daughter was just too stressed out senior year and skipped one of her AP tests. This of course meant that she did not report a score for that particular AP test. There were no consequences, other than not getting AP credit for that one course. She still was 6 for 7 in university admissions (or was it 7 for 8?), still went to a very good university and did well, and still got admitted to a very good graduate program (where she is studying now, with a bit less than one year to go). A year from now she will still be called “doctor”, and missing one AP test will be long forgotten (and a B- in organic chemistry was similarly not a problem). No one is perfect. We do just fine anyway.