As a founder who struggles with severe depression, one of the few bits of advice that I remember when personally in a dark place is from a physician that had met with thousands of suicidal patients. He said:

"I've never had a patient who survived (suicidal thinking) and later wished that they had killed themselves."

Sorry I couldn't find the quote and may be paraphrasing a bit, I share this because this personal mantra has kept me from the ledge when my thoughts were otherwise debilitating.