Ups and Downs

I just got back from my 4th weigh in for a weight loss contest at work. I lost 0 pounds, but didn't gain either. I am extremely frustrated. Here's my track record:

Week 1: -8
Week 2: 0
Week 3: -3
Week 4: 0

This week I started a little weight training (4 times a week) a workout designed to keep the muscle you already have and burn fat. I also have been doing interval training 2-3 times a week.

The ladies at the health clinic told me that the 1700 calories daily could be too much. I am a 32 year-old male, 5'11" and currently weigh 223. I don't always even get to 1700, but that's the total I was given for a 2lb. weekly loss. I will say that I follow the plan 6 days a week, with Saturday being a kind of cheat day. This lifestyle is so much better than the way I used to be, however, my loss is rather inconsistent.

Any thoughts and/or ideas?