OOOh ick, that is a drug you shouldn't do that with, there isn't any flexibility with that drug at all, it's not like lithium where you can up it a bit. Was this purposeful? are you sure it was just a double dose, if it's more go to your local ER, it could make you seriously ill. I would suggest if it's just a double dose, it will pass, I did that on celexa once and I was green around the gills. I'm forgetful. I have a med dose container, that has all my specific amounts of drugs I need that day already set out. It might help.
Drink a lot of water, the drug has a half life I believe of 12-24 hours, it will flush through the kidneys as well help with your liver. If you still don't feel well go to your ER, it couldn't hurt.Call your pharmacist too! Much luck, hope you feel better.
Was this an accident? Or because you weren't doing well and you raised them on your own to see if it would help which is never a good idea? What is the dose that you are taking? What dose did you take today? I could give you some more information then. But more importantly if you are starting to feel sick then you might have taken above what is the reccomended maximum dosage and clearly you are encountering some side effects. I don't know if they will get serious or not but my suggestion is that you call your psychiatrist and them what to do from here. I know with some of my medications if I took too much I would feel sick and with some it would be outright dangerous so I can't say specifically for yours but your psychiatrist could. But if you want more information on anti-depressents in general and what are the options and proper dosaging go to "Depression Central" which is a great resource but please speak to your psychiatrist regardless.