I've been researching this a lot longer than you.
And like half of my family are either Doc's or Chemists, not even including myself.
Serotonin does not increase dopamine necessarily.
It can do either; it can increase it or decrease it.
And brain regions are most important so if you want to get technical, you would be looking at the Raphe nucleus neurons and how they relay feedback to cortical areas.
5-HT1A/1B receptors "enhance" dopamine, but they also serve as "negative feedback".
They end up dropping the serotoninergic "tone" back down which is responsible for the delayed effect of SSRI's.
Then, after a few weeks the receptors that
control neurotransmitter release don't work as well - "desensitization".
This leads to more serotonin and possibly glutamate which then reinforces dopamine.
Next are epigenetic changes. Some subunits of receptors in the hippocampus and Prefrontal Cortex like NMDA-Subunit 2A get decreased.
This is supposed to be responsible for enhancing the basal (
resting) glutamate level in some brain regions.
As a result, there is a selective enhancement of glutamate levels (and accompanied by a selective deactivation in some areas closer to NMDA terminals).
-->
https://area1255.blogspot.com/2015/02/does-serotonin-raise-dopamine-or-lower.html
Additionally, Celexa (Citalopram) most certainly DECREASES Dopamine D(2) receptors, in HUMANS; this leads to increased Prolactin.
Not exactly consistent with a "supportive" effect. -->
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4617661/
In other cases, dopamine levels fall low enough to create Anhedonia (lack of pleasure) in human patients taking the drugs.
--> https://www.ncbi.nlm.nih.gov/pubmed/20034615
Now in your case you may not be experiencing that - but some users are more sensitive to those effects and derive less benefit from them overall. This is documented time and time again. Many users do not respond to SSRI's
AT ALL.
-->
https://www.ncbi.nlm.nih.gov/pubmed/9786309
The dopamine increase is variable. It happens in some and in others not so much. There is no guarantee with SSRI's.
Finally, SSRI's "require" brain histamine to actually DO ANYTHING.
--> https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4648163/