Almost nobody wakes up with sweet breath. Brush our teeth because the taste in our mouth is unpleasant. Daytime causes of temporary bad breath are mostly caused by foods we eat such as raw onions, garlic, cigarettes and alcohol. These can be temporarily masked with mouthwashes and mints. Persistent bad breath can be a signal that something is amiss.
Periodontal disease is a major cause of chronic bad breath.
I weigh about 130 lbs, but I lift weights and everyone says that my weight is ok. It sounds like you are experiencing teenage angst about your weight. One must consider many factors in determining a good weight. How your clothes fit is usually a good clue. It is true that muscle weighs more than fat so many weight lifters weigh more than their non weight lifting brethren but not to the point of being overweight.