there was a point for me where I lost 7% body fat and 13 inches but actually gained weight. I would encourage you to take measurements and get someone to properly measure your body fat (someone trained to do so that works at a fitness center)
If I didn't have those other ways to track my progress and went just off the weight I would have been soooo discouraged.
The good news is that if you keep it up and eat accordingly the muscle that you are building now will start to burn more calories and the number on the scale will eventually start to shrink.. and what you're doing is great for your heart!! :)
Actually muscle takes a lot of hard work with heavy weights and usually a caloric excess to build and it's not done in a week. You can, however, get stronger and lose inches on a cal deficit. What you are seeing are water fluctuations due to your muscles getting used to a new activity. It should drop back down as you adjust. In the meantime, stick with your cal goal and keep working out :)