Sorry you're having difficulty with depression, Sadley. And, yes, it is very possible to be medication resistant.

Ask your psychiatrist what he/she thinks about a relatively new food medication called
Deplin which can cross the blood-brain barrier to provide folate (vitamin B-9) to increase
serotonin neurotransmitters in the brain.

70% of depressed people are lacking the enzymes in the stomach that metabolize
folic acid into a form the brain can use. I know of one medication resistant person
for whom Deplin works. It takes about 2 weeks for improvement to begin to show, but it's worth its weight in gold if that is the cause of your depression.

Genetic testing will identify it, but your psychiatrist might be willing, (as mine was) just to prescribe it and see how it works. If it works, there's no need to undergo genetic testing.

Look back at your family history on both sides. Has anyone in your family had trouble
with depression besides you? Things of that sort may be a clue to you that depression
is inherited in the family in some cases.

I genuinely hope you find the things that work, because I know that it is no fun suffering
from depression.

Good wishes.