How do I loose 46 lb in 3 months?

Carefully! 46 lbs is a lot for 3 months. You need to be sure your losing weight safely and not just quickly. I am a big fan of the zero carb diets like paleo and 4 hour body. All diets however need to be in conjunction with healthy exercise habits and common sense. Try to avoid meds as they form habits that usually don't stick. Shoot for long term goals as well. Consult your doc before starting to be sure.
Weight loss. That amount of weight loss in that short of time period will require a strict diet, regimented exercise program with significant amounts of aerobic exercise. You should consider getting a trainer to help you along the way.
See a dietician. You can see a dietician. But recently i started weight loss program in my office called HCG diet, 43 days course, expected weight loss is up to 35 lbs (1-1, 5 lbs/day!). Very effective. Look into it.