hi facko, welcome to PC
I can relate to a lot of what you're feeling. I'm also prone to feeling guilty, usually over trivial things, or sometimes nothing at all. For me it's a manifestation of my depression, along with low self-esteem, anxiety, a sense of being different or set apart from others, and just general not-feeling-good-ness. Obviously everyone is different, but in my case the depression started out by coming and going, until there was more coming and less going. I'm glad that you're not feeling suicidal right now. It's a good indication of where your depression is at, so if you notice a shift in that thinking, it's a sign you need to get further help.
If you don't feel medication is right for you, then don't take it. It's good you're seeing a psychologist -- maybe just concentrate on talking about your feelings for now, rather than dealing with medication. After you've done some talk therapy for a while, if you still feel that your depression isn't getting better, then maybe you can re-evaluate.
To be honest you sound much more aware of your depression than I every was, and I'm really impressed at how well you seem to be monitoring yourself. Keep it up! I hope you keep us posted on how you're doing, and I hope that you get some relief soon.