Shivatar,
First, thank you so much for sharing such a personal experience. I'm glad you can look back and see how profound and amazing it was. Not everyone is lucky enough to have such a life changing event that confirms the belief in life after death and that we're not alone.
To clarify; when this happened, you hadn't taken any harmful substances correct? I almost wanted to say it sounds like you had an NDE, but you didn't mention actually going through with your plan. I have not had an NDE, but have read many accounts. I noticed a few similarities between AP and NDE, however there are many important differences.
With that being said, it is my belief that your dark thoughts and plan to end your life are what triggered your experience. This isn't the case with everyone, so I'm inclined to think you were already beginning to open up spiritually and perhaps gaining awareness prior to this event. I've also thought about depression at length. In many cases, I believe it to be a sort of side effect of being aware or 'open'. So if an individual is aware/open, they become more sensitive to the world around them (seen and unseen) and then become overwhelmed, which causes depression and perhaps other 'mental illnesses'. Does this make sense?
Your experience, whether AP, NDE, or something similar was meant to happen for you to understand what you are; A perfect soul/spirit navigating an imperfect world. To know you are not alone and that you are always supported, guided and above all, loved immensely. I believe it also happened so that you could open your eyes and soul to others here, going through similar situations.
While our soul is perfect, our human side or ego is not perfect, but that's alright too. It's all a part of the learning process. Again, thank you so very much for sharing your experience. I know it will help others in a similar situation. I tip my hat to you!