Usually you are awarded one degree from a university (with one or multiple majors). Most colleges have extra requirements and classes (language, math, social sciences) that you take, which while aren't in your major, count towards a degree. Unless you satisfy these requirements TWICE you are only awarded one degree. An additional degree usually means a lot more college.
In your situation it sounds like you've earned either a BS or BA degree, with biology being your first major and chem your second. You can always also ask your prehealth adviser about this as well.