Couple of points here. Some instructors like to be contacted in certain ways. Many do not like calls at home, and you can't blaim them. If he didn't return your call for three days, you might have been annoying him. Most instructors will not let this affect their grading of you, but annoyances can never help. You usually can't go wrong with dropping in during posted office hours. These hours are kept by every intructor and are specifically available for outside class discussion. Also, talking and studying with other students can be an invaluable help in difficult classes.
There is no such thing as a "perfect" paper. Constructive criticism and an honest grade is more conducive to learning and is much more valuable than a pat on the back and an "a" with no suggestions for improvement. About APA, I've not written with APA, but I have written and dealt extensively with MLA and Bluebook citations. You have to keep in mind that formats change rules frequently and instructors will not always be up on the latest thing. If you went by the book and got docked, point it out to the instructor. However, it's still safer to put the writing in the format he or she wants.
Finally, we have a lot of ways to view the things in life that happens to us. We can view a poor grade as a slap in the face that was unwarranted. We can also view a poor grade as an indication that we need to give up or that we are a failure. The most beneficial way to view a poor grade, however, is as a great opportunity for improvement.
I realize that you probably just wanted a sympathetic ear and some consolation, but I'm not equipped to provide such things. ;-)