Don't worry !
I can assure you, that if you've lost inches as well as weight, your body fat did not go up. Your personal trainer must have made an error in their calculations. Losing inches tells me you're losing body fat. So, don't assume something must be wrong because one calculation doesn't seem to jive with the others. People do make mistakes.
How long ago did they take the last calculation ? Ideally, your PT should only be testing you once a month. It takes at least a month to see any subtle type of change. If your PT is taking your measurements every week, then yes, there is definitely margin for error.
Take a deep breathe. You really are just doing fine !!!