The more you weigh the more calories you burn every day. Just being alive and carrying around more weight means you have to have more muscles to do that work and that is where you burn the calories.
Imagine a 115 pound woman walking one mile, now imagine her trying to do that carrying 110 pounds....
Some of that would have been water weight, so, no worries sounds like you are on track!!
I find it is motivating to see a lot of progress in the beginning--it makes you just want to keep it up.