Welcome! You shouldn't feel guilt over this long ago attempt, it was YOUR life that was almost lost, not one of you're family members, I'd recomend you seeing a therapist, he/she'll tell you that this is just an irrational thought, and probably brought on by overanalyzing, often a symptom of depression and/or anxiety. (I studied psychology, but I'm also a patient) I hope this helps, at least a little bit, I know your family doesn't place blame on you, they are just happy your alive and well.