You CAN DO this, girl. Even with this small step back, you've lost 15.2 pounds!! That's FANTASTIC!
As far as getting back the motivation--remember ALL the reasons you started this diet. Make a list, if it helps. Visualize your life when you get down to 140. Think of how much better you feel; healthier you'll be. Do whatever it takes to get your mind and motivation where they need to be in order to reach your goals. You're a strong woman. YOU CAN DO THIS!!!