Hit my plateau :(

715hopers

Hi, this is my first forum post here. I'm a 32 year old female, married, no kids yet. My weight loss goal is 20 lbs. I'm 5'3" and started at 150. I have been on MyFitnessPal for 2 months (started on Christmas day!). About a month ago, I stopped losing and have been fluctuating around 141-139. For the past two weeks it has been at 139.4. I'm not sure what to do! I exercise 5 x's a week, as much as my schedule allows. I go over on my limit every day a bit, but it's mainly because I have a medical protein supplement that I HAVE to take...(this is for medical reasons, it's not optional) that is 560 calories a day. Anyone else at a plateau? I haven't been very conscious of WHAT I eat, just the total calories, so I do still snack a lot. What can I do to get the scale to move again? i'm trying to just be happy about the weight loss so far because it has been almost 3 years since my scale has been below 140.