You have increased your exercise, thus you will be building up muscle, even if you cannot see it yet.
This can often lead to feeling depressed because the weight isn't falling off. I've been there. It is far FAR better to take measurements of the waist and stomach, and thighs, and not be a slave to the scales. Inches can drop off without weight changing at all.
Also, if you are doing 10 minute sessions, i found the '10 minute solutions' workout dvds to be amazing. It's a lot easier to stick to than things like step ups, as there are various sections. It's also ideal for a hectic lifestyle due to needing only 10 minutes at a time. I've done the pilates one with Susan Bowen for about 6 months, and along with a healthy diet, I've lost 7 inches from my waist.
Hope this helps, and good luck. Don't let it get you down!