Accuracy of the Runtastic App?

I am a 23 yo male that has been wearing the runtastic heart rate monitor for about 20 hours so far to see how many calories I burn in a 24 hour period. At this point, it says I have burned over 5,000 calories and I didn't even work out or anything? I have been eating about 3,000 calories per day and going to the gym and not seen a change in my weight so I am wondering if this app is a little exaggerated?