Agree that it’s not so important to take so many classes. See if you can focus on what you love rather than the race to get “ahead”. Do not panic. The worst-case scenario is that you get bad grades in a few classes. This is not the end of the world. First, there are plenty of good schools that take B students and even C students. The list came out this past week of the schools that didn’t fill as of May 1. Some really great schools that didn’t fill include Hampshire College, SMU, Guilford, several SUNYs, Ohio Wesleyan etc. Colleges want you to think that they are impossible to get into. The fact is that many many of them are not so hard to get into. Here is the list of schools. It changes over time, so you may not see some of the schools I mentioned, but they were on there earlier. On the other hand, you may see some schools that weren’t there the last time I looked–http://talk.collegeconfidential.com/college-search-selection/1889549-colleges-with-openings-for-fall-2016-nacac-annual-list.html
Second, you can start at a four-year college that you may find not so desirable and transfer into a college that you prefer. You may discover that you like the first college and never transfer.
Third, you can also try working for a year or two after high school, attend community college and transfer into School of Dreams (or one closer to School of Dreams in your mind).
There are so many ways to go to college. You can relax a little. This is not a race. You have all of the time in the world. Breathe and sleep and exercise. Eat well. You’re going to be fine.