I've tried sertraline, then citalopram, now on mirtazapine and venlafaxine. will these drugs ever work ? losing hope.

Add CBT therapy: For decades research has shown that optimal therapy outcomes require therapy - it enhances medication and for some is sufficient alone. The need to learn symptom mgmt skills cannot be met w/out it. Don't lose hope - it is also a major part of successful treatment. In fact, w/out confidence it is unusual for any treatment to be a success. So, find a therapist you trust and work at it! Best!