Im 19 years old, 148lbs. & 5'3". i started to run on & off since may @ 145lbs. & gained those 3lbs. what will really help me lose weight fast?

Exercise and diet: They have to go hand and hand, with a normal bmi you don't qualify for prescription appetite suppressants or bariatric surgery. If you want to lose more body fat drink only water, eat only lean protein, vegatables, and fruits, avoid sweets, fried foods and processed carbs (breads, pasta, rice) and watch your total caloric intake. And keep exercising of course. There's no magic bullet.