Ethical contradiction quiting toxic job

Hello fellows. I have a moral/ethical issue quitting my current job. As my first job I wanted to give everything from me to do a great work, to become a "real" software developer, to be recognized by my colleagues, manager and friends. I was so naive. Never though about abusive and toxic people are the people that are occupying the higher positions on the corp's ladder. I committed many mistakes putting myself on jeopardy because I wanted to be honest and proactive say "yes" to every task that was assigned to me. Eventually everything went wrong and I only realized when I had 3 big projects as the ONLY developer at once (startup shit). Lockdown, 10+ work hours a day, no social life hit your body and mental health really hard by the 5th month. I want to leave my company and the really nasty incompetent managers but these 3 projects will die and many legal problems will derive from that. I know that is non-professional to leave in this circumstances but I swear I am on the borderline. What can I do before I become suicidal?
Sorry for my English.