Whenever any kind of problem arises that affects your academic career at UArizona, be sure to get in touch with your academic advisor right away. You did the right thing to contact your instructors, but advisors can inform you of policies and your options in such situations. Since your grades have already been posted, you could file a General Petition requesting retroactive withdrawal. See your advisor to discuss your situation and to get more information about the options available to you.
All the policies and university-wide regulations regarding courses, exams, grades, graduation, registration, transferring, etc. are available online in the General Catalog. If you need help understanding policies, see your academic advisor.