Exactly how were you training from October until last week?
What's your strength like on the basic lifts - squat, deadlift, flat bench, overhead press, row, and pull-up/pulldown?
Also, it's not really a good sign of things to come, that you've dramatically switched goals after just two and a half months. Try to set more appropriate long, mid, and short-term goals that snowball into each other for continued progress.
I'm not being condescending or sarcastic, but why do you have to get to 200 by March? Going on a trip? Playing a mental game with yourself? Do you think that someone weighing 200 pounds at your height is your ideal physique? (This is also kinda what Obsidian was getting at.)
Also, why were you "so focused on bulking up" in the first place?
This, with smart eating, really should be plenty to get you where you want to go. Consistent lifting, basic cardio, and the right food choices.
Some nutrition reading:
or, more "extreme" (insomuch as a whole food diet can be "extreme") http://www.T-Nation.com/testosterone-magazine-635#green-faces-diet
How tall are you?
Any chance of tossing up a pic to see your current condition? Or at least, can you describe your current level of un-leanness - obese, pudgy, Average Joey NoMuscles, already ripped and insane to consider getting 25 pounds lighter?