I have dealt with some depression but it was a physical thing not brain chemical thing. I had gone through a stressful period with an abusive boyfriend and my health had suffered. My poor health combined with the stresses that I had gone through caused me some trouble. Once I got a handle on the health part of it and got a chance to talk through all the upset I had gone through, then I started to get past the depression.
My Dad has had trouble with depression big time. He has made repeated suicide attempts to the point where the psychiatric clinic started refusing him when the police brought him there and sent him to the hospital. I know you said that you don't have suicidal thoughts. I agree you can almost feel more down when you aren't thinking about suicide. When you have suicide on the mind you almost feel like there's a way 'out' so to speak. Not that it's a good choice to get out but that's the way I felt.
Has your Dr checked your health in certain ways? There are many physical problems that can cause depression. Thyroid, Anemia, Cronic fatigue, and so many more things that I don't even know of specifically. If they haven't checked any of those things and you've told them about your depression I would go elseware. My dr checked the physical right away.
Also Hubby had some mild depression that he dealt with a couple years ago. The dr started him on Zoloft without any problem. He wasn't suicidal either. I feel that depression should be handled before it gets to that point if possible. I really hope you can find another Dr who will take you seriously. Not be afraid to ask them to check your thyroid and hemoglobin. I know those to things. Make sure they look at all possibilities.
Here's a list of some medical reasons for depression.
WebMD