Hello Pre,
Your story sounds very familiar. I am a 46 year old male who has dealt off and on for years but recently got worse. Before any POTS diagnosis I was told I had depression and anxiety and tried almost every med out there, including Fetzima. I remember Fetzima clearly because I felt it was working great and after about 4 weeks it made me very manic! I was up for two days making plans on writing a book or two, moving furniture, cleaning and overspending. Did not go well. I tried different strengths to no avail. For whatever reason I seem to have a very bad time with SSRI and SNRI's the main problem usually is sexual side effects but there have been others as well (headaches, sweating, etc.). Being a man with no drive does NOT make depression or anxiety better I have learned that, especially when married!! I am currently on Trintellix (formerly Brintellix). It hasn't helped POTS symptoms much but does tamp down depression or keep my mood more even. I have been on it for about 10 months and it's been..well, EH! Not amazing, The sexual side effects tend to wane, some days are ok others not so good. I would love to be more help but as I say for whatever reason I tend to exhibit most side effects from psych meds. I can say for sure my least favorite was Cymbalta, I had withdrawal brain zaps from that for at least a month! No fun.
Also, instead of the tilt table you can try the old fashion way. Supine, sit, stand test. My Cardiologist did it first in office, Basically keep a Heart rate monitor on an check it after 2,5 and 10 minutes in each position (although he only had me sit for 2 minutes) a jump of 30+ bpm from supine to standing is a good read for POTS. Hope this helps.
Best of luck!
-A