Hi Matthew,
There is a section of the child support guidelines on page 21, section IV.E.6, which gives an example of additional employment and how child support can be affected. Essentially if you had both jobs before the divorce and the family relied on that income, both incomes would be used. But, if you started working another job after the divorce in effort to help meet your financial obligations to your children, then the court may justify a deviation and disregard your additional employment for purposes of child support.
If I were in your shoes, I would contemplate making a copy of the relevant pages of the child support guidelines and discussing with your attorney the possibility of entering an "overall financial condition" adjustment on your worksheet to allow the court to disregard your second job.