I personally would take the dosage prescribed, and discuss your findings with your doc, maybe you just need a change in dosage, it is best to check than risk things.
I had been on Celexa a few years ago, unfortunately I had SSRI's "poop out" then my type of meds were changed, but I must say when I first started with Celexa, my depression lifted for almost 2 years, this sort of thing happens with some people.
I definately feel you should consult with the prescribing doc about your med(s) and dosages.
Please take care,

DE