Actually visualizing the act should set off every warning bell. All too often, a suicidal depression catches us alone and off-guard. Notwithstanding all we have to live for and all those who care for us, the brain in crisis has a perverse way of having us think the very opposite. Remember, there is no shame in reaching out. Your other option is calling your psychiatrist or getting yourself to the emergency room.
Time is of the essence.
Do not delay in seeking help. Do not be put off by the bad practices of some of the health system's gate keepers. Finally, take comfort in the fact that help is on the way. Your brain at the moment may not allow you to think hopeful thoughts. But it cannot keep out the knowledge that others are hoping on your behalf.