Your stated basis for appeal strikes me as lacking merit and is likely to earn your more sanctions, as the judge appears to have believed that you'd not have the burden come September. Instead, I advise that you get the matter back before the judge to get a modification of the order's deadline for commencing payment (but be prepared for attacks on your lack of finding work). Maybe you (esp. via an attorney) can negotiate terms of payment that work better for you.
The court cannot find you in contempt if the order was based on imputed income. The court still needs to find that you have the ability to pay, that there was an order. The requirements that they have to prove to the court is that there was an order, and that you were aware of the order, that you didn't comply with the order and that you had the ability to comply.
If after they put on the case, ask them if they are resting, and if they did not meet any of the above requirements, ask the court to dismiss the contempt. Also, the standard of proof is higher that most other family law cases, as it is a quasi-criminal action.