I did a bit of internet research on that three med combo. I can't find anything that would suggest the three would produce any "bad interaction."
That doesn't mean they won't, I'm just saying that I do know that Gabapentin can be combined with other anti-sezier meds like Abilify. Now, logic would say that a simple SSRI like Zoloft would not cause any issues, but don't take that as fact.
If your seriuosly in doubt about that three med combo, you realy should ask your Psychiatrist just to be sure.
google "drug drug interaction" and you will find options for checking medication interactions....i use one of these sites regularly and some allow you to set up your own medication profiles. good luck!