i have taken a few meds for depression and none of them seem to work well enough to make up for the shitty feeling they gave me.
this thing called "synergy" its the effect you get when you mix 2 drugs
any 2 drugs and it varys from person to person and drug to drug.
its almost impossible for your doctor to say that the synergy YOU get from mixing your meds and weed is messing you up. while at the same time he cant say its helping either.

the only one who can decide that is YOU because YOUR the one who feels it.

i say you should explain that to your doctor
and work with him some, quit for a week or to so you can honestly tell him if mixing the weed has any bad effect on you with those meds.

and you might want to try other meds if your doctor is any good he should change your meds for you but dont belive that b.s. about "you need to take these for a few months to get the full efect" they are told that by the drug companys because the drug companys want you to buy the pills for at least a few months