I know i've got depression, i don't need a doctor to tell me that. but do they have to prescribe anti depressants or what?

It depends: There are 2 major types of depression 1) reactive to disturbing life events and 2) physiological. Then there are those that are mixes of the 2. The physiologically based depressions can not be cured, but medication + psychotherapy can help keep them under control. Reactive ones need more psychotherapy to deal with the issues underlying the depression and may not need medication.