Well, you can trade forex at up to 50x leverage, so you could definitely lose half your money in 3-6 months. But maybe double it.
The really sucky bit here is (I've had that happen) when the market then immediately turns - you simply couldn't buffer the immediate losses ;-)
Lots of shady stuff about and what many people don't realize in many (most?) cases of consumer internet platforms (like FXCM), one is actually trading against the company (they are the market maker) not against other participants. Not saying what does or doesn't happen, but the situation is such that there is incentive to do things like widen spreads and hit stop losses.