Active job and can't lose weight

I started a new job about a year ago. I went from desk job to 14000 steps in my 12 hour shift. When I was at my desk job I was losing weight. I just started back actively counting calories about 6 weeks ago and only lose 4 lbs. I am getting very frustrated and don't want to give up. Any ideas ? I am very over weight too I need to lose about 100 lbs.