Welcome to NeuroTalk.

Your supplements so far are good choices. I have to wonder though, if you are having problems with serotonin manufacture.
Magnesium and B6 are cofactors in synthesis with tryptophan.

The 5-HTP is an intermediate step to serotonin.
Therefore I'd suggest a good B-complex to provide B6.
You can do a B50, or B-right by Jarrow if you don't like the high doses.

Another factor especially if you have sleep issues, is B12. The activated form, is a cofactor in melatonin synthesis, and may help
1000mcg (1mg) of methylcobalamin daily on an empty stomach.
The form in multivitamins or B-complex is usually cyano form and some people cannot activate it to methylB12 properly, so are functionally low.

It appears to me though, that you are on the right track.