You can mix an SNRI with SSRI, or Tri-cyclic with SSRI, Tetracyclic with SSRI, mood stabilizers such as Eskalith, Abilift or Lamictal
can also be mixed with SSRI's and SNRI's. But never two SSRI's together
for long term.
Maybe during a med switch when your tapering off one SSRI and slowly introducing another SSRI, then fine, but not the two together for more than a few weeks during the switch.
Find another doctor because I would not trust any doc that had me on two seperate SSRI's like that.