Hi, I am a senior and have only taken three ap classes. My current course load includes five ap classes and one college class, speech. I am considering taking an additional college class this semester in order to show my use of all sources available to me (my school only offers 8 APs, so I will have taken all of them). I also took psychology 101 last year. Would this additional class be beneficial for my application?
Also, I am very interested in classes such as European history and world history, and I feel that I would enjoy psychology, human geography, and environmental science as well. I am considering self studying for these classes and taking the ap exams at the end of the year. Should I do this? Is there any way to indicate that I am self studying these classes on my application? This may be a stupid question, and while I am fairly certain it is not possible, I want to be sure. I come from a school where nobody is particularly motivated to get into a highly selective college. For example, none of my friends have even heard of the PSAT or SAT II subject tests. So no one has been particularly helpful, including my counselor.
Thanks for the help! 
5 AP courses and one college class are enough. Your schedule is already very close to being overloaded.
By the time you have graduated, you will have taken the toughest program available in your high school. That is what matters. Save your energy for your application essays and for the classes that you are enrolled in.
Thanks for the advice
I agree that you have achieved the highest rigor at your school already. Nevertheless, it is up to you if you have the ability to take more challenging courses without affecting your GPA. Having more AP and college credits may potentially accelerate your bachelor degree and save some money.