Is it bad to think about suicide? It does not cross my mind as a "i want to harm myself" every-time, but on occasion does cross my mind as a hypothetical.
I have also been told by people in the mental health sector that an awful lot of suicide is impulse. It's why they say the element of human connection which is behind the homily of asking "RU ok" is effective: it breaks the moment. It's hokey, and it's massively oversold but for people in isolation, simply being engaged with can be enough to prevent a tendency to act, which was on the brink.