What are some natural supplements I could buy to boost my gaba, serotonin, or other natural chemicals in the brain?

I feel that I have a pretty large deficiency when it comes to things like serotonin because of my crushing depression. I feel like maybe a little more extra effort from me might increase the effectiveness of my SSRI medication, or just improve my over all mood.

Once again I am looking for over the counter vitamins not the prescription that works best for you. I already pay a doctor an arm and a leg to figure that part out.

Lastly, other than the B vitamins, are there any vitamins that improve over all energy levels?