First of all congratulations on taking the first steps on becoming a better you! 

When trying to lose weight there are many factors that are involved, the most important being DIET. At times when people are just watching what they eat they still eat "unhealthy" foods necessarily. A good diet of enough protein, carbohydrates and fats is needed to allow for your body to function, but at the end of the day your body must be in a caloric deficit.

By this I mean the energy output (exercise and general energy exerted throughout the day) needs to be more than the energy input (in this case the food that we eat).

In terms of your exercise, I personally don't know your body type but at times multiple days of exercise are needed to see results. Every Individual is different, and perhaps by changing your diet and keeping the same amount of exercise may work, or it may not. I recommend monitoring your weight and see what works for you. 

Hope this helped and let me know how you go!