I've actually experienced what my pharmacist thought was seratonin syndrome when I started taking Cymbalta while taking Remeron (psychiatrist prescribed). I was full-on high. My understanding is that Welbutrin is more of a Dopamine/NE modulator... With some seratonin interaction but nothing like an SSRI (which is likely why it helped me and SSRIs and combos of SSRIs didn't - I don't have a deficit of seratonin... And that's likely why I felt like I was high from the double seratonin hit with the combo).
Anyway, I'll prob avoid 5-HTP for now and see how this plays out over the next few weeks.
If you don't already, keep a diary noting how you are feeling, even track your period, even noting any non-primal type foods you may have eaten, etc on a daily basis. I have been doing this for over a year and it is extremely helpful in seeing patterns, and in presenting the data to your dr. I do think the seasons also play a role in how a person feels and hormone balances...in winter people can tend to be more down, in summer people may be more excited....it's worth trying.
Just a thought but since I started basically eating a low (well...much lower) histamine diet my anxiety is much better! If you google "high histamine and anxiety" or "high histamine food and anxiety" there is some info out there. I know once going primal I started eating more tomatoes, avocados, spinach, almonds, kimchi and other fermented veggies etc. There are both high histamine foods (vinegar, fermented foods) and foods that release histamine when eaten...chocolate, avocados, many fruits etc. I was so relieved when I realized that by lowering my histamine levels, my anxiety improved.