DG, don't panic. You have time to figure this out. You have until August.
First of all do you have a Separation Agreement in place? Is H contributing to your household and mortgage expenses? If so that could count as income for you and that may help you to qualify. If H is not contributing anything you should talk to a lawyer.
Do you have any equity in the house? Have it evaluated by a Realtor. Maybe if you have to sell it, you'll be able to buy something smaller that you'll qualify for.
BTW mortgage rates are supposed to start going up in the next few months (in Canada). Are you aware that you can get pre-approved and lock in a low mortgage rate for up to 3 months before renewal?
M53 H54 D17 M33Y T38Y Bomb OW 09/09 OUT 10/09 BACK 11/09 OUT 01/10 WANTS TO R 04/10 BACK with OW 05/10 Wants to Reconcile 05/11 I said NO