Fitbit One

Good morning:). I purchased a fitbit one a couple weeks ago to get my accurate tdee to use as a guide because I had no idea the right numbers to use for calories needed.. Over the past 2 weeks I have averaged 2800 calories burnt in a day and 17000 steps, which I never imagined to be so high, I run a daycare with 8-10 kids so its busy. Currently I am trying to eat a minimum of 1500 calories and a max of 1800, but don't focus a lot on my "Net Calories" as long as I consume that amount. Is this to big a deficit? I am so leary on increasing my calories but am definitely struggling to get off this last 10 lbs but don't want to gain what I have lost, 37 lbs since November. I also have my activity level set to lightly active on mfp. Anyone have any advice or have experience with this.

Age 33
Height 5'8
Currently 154
Goal 145
Workout 5-7 times a week, mix of cardio and weights, an hr to an hr a half a day.