Did he tell you what biochemical disorder he thinks you have? That is a pretty vague statement. I would ask him for more details.

If it is depression, you can also try to work on that in therapy without meds, or do a combination of meds/therapy. Another disorder might have different options. But you needn't feel pressured into meds if you are uncertain. You can always try other solutions first, then try meds if your other approaches aren't working. Meds can indeed be really helpful to some people.

I have largely beaten my depression, but occasionally it comes back. I remember a while back I told my therapist I'd been depressed the previous week. Just under a cloud. All the symptoms back immediately--feeling down, moving slow as molasses, inability to sleep, exhaustion, anxiety, etc. Everything back in a flash. He was really concerned and asked me why this was--was it hormones, biochemical, or situational? My response was "everything is biochemical," and we laughed and he agreed. I can't see how my answering that question with one of his options would have influenced anything we would do in therapy. We always feel down due to what is going on with our neurotransmitters and such in our brains. It's all biochemical. I don't even get his question, and he realized from my answer to him how irrelevant it was. Then we got down to work and looked for the root causes and what was truly bothering me to have brought this on.