What might happen to earth's climates if the earth were not tilted on its axis.

It would either very hot or very cold. No in between.

The side facing the sun would remain around 40-79 deg. Fahrenheit (5-30 deg celsius)

the side facing away from the sun would be dry, moderate or continental

Although this may be the opposite of what you think i will say it anyway. you were brought into this world for a reason and you still have soo much ahead of you. not everybody has an opportunity of living a great life, but it doesn’t give you a reason to end everything. somebody in the world loves you, and imagine what you would do to them if you left forever.