I need answers NOW!!!?

17 yr old girl, like 164-168, 5 foot 6 (yes i am overweight) and have been a yo-yo dieter for about a year and a half =/ I've been at my lowest weight 149 and now back in the 160's. I lost the weight last yearfrom going to the gym 2 hours a day and eating about 900 calories. Then my body went into starvation mode and I NEEDED to eat. I was sent to the hospital with stomach ulcers from starvation and now have been working out for 2 hours a day, (sometimes 3) and have begun to see changes. I need to lose 30 lbs in the next 2 or 3 months and I KNOW this much working out isnt dangerous. I have a lot of body fat to lose and know that if i limit my carb intake and eating veggies, fruit and whole grains i can lose the weight in a short period of time and keep it off; So my QUESTION is how long until i lose the weight?!?!?!?!?! (wow this is alot) sorry! just please help me!