Hi Michelle
You have a beautiful body.
Can you give a little more detailed info so we can know specifically what you are doing now? "Clean diet" may or may not be sufficient for your goals. I'm going to say what is generally in the "Are you new to EF Women's Board? START HERE" sticky at the top of the board.
Can you list your typical day's meal plan? E.g.
Meal 1: 8 am
1/2 c oatmeal
1 whole egg
1 egg white
1 scoop protein mix
Meal 2: 11 am
2 oz almonds
Meal 3: 2 pm
4 oz chicken
2 c broccoli
4 oz sweet potato
etc.
Even better if you can put it into a food counts program like
www.fitday.com -- its free & onilne - takes a couple minutes to configure but very easy & quick to use. It will tell you the total calories for the day as well as the macro-nutrient breakdown, i.e. % protein /% fat / % carb. This is a really good exercise to do because people often think they are eating "clean" and "enough" but they have never actually enumerated the actual amounts they are eating & what they are eating. It is very enlightening. If you can post this then we can make more specific suggfestions & comments. Otherwise its really just guessing on our part.
Are you doing any resistance training? This will be a critical part if you want to increase muscle mass. Cardio alone won't do it.
Finally - I wanted to point out the more important thing to watch- your bodyfat ratio (ratio of lean muscle mass to bodyfat) - this is more useful than just looking at the scale. The scale only measures the sum total of your bone, muscle, bodyfat and water weight. The number on the scale is not going to really tell you anything useful about your bodyfat when it measures 3 other things, one of which, water, can be the source of a 10 lb weight swing easily just based on what you ate that day (e.g. high sodium will make you water retentive). Bodyfat measure will tell you more about the composition of your body.
Can you get someone at your gym or your bf to do regular bodyfat measures so you have something more useful to measure your progress by? Even just looking at how your clothes fit will tell you more about changes in your body composition. For ex, if you are increasing your muscle mass, you may not see your weight go down, you might even see it go up, but you should also notice that your clothes are fitting looser because muscle mass takes up less space than bodyfat.