I have mdd and i have lost all sense of taste. everything taste like cardboard. is this normal or is it a medication side effect?

Possible Nocebo: There was research that linked such medication (and others) to taste/smell impairment. It was before many new drugs were marketed. Also the conditions themselves have been linked to loss. But, whatever - you might be affected in part by the expectancy and that matters too. I'd imagine it possible that a switch to psychotherapy and perhaps a different drug is a good idea for you. Belief matters!