I was never truly happy...
that's when you know I led a pathetic uninteresting life.
To answer the question,
I wouldn't tell myself to kill myself just then,
Because alternative universe is a thing based on what decisions you make,
some situations where perhaps there's no way you can change what already happened,
but hypothetically if there's a way to fix your problem, you might wanna go back in time and tell yourself to go a different trajectory and try something else instead of wasting the time on your current pathway since it's not working so well.