I am only 13 and already I am obsessed with babies, pregnancies and bumps, anyone know why this could be

Sounds about right due to puberty and the mess that are your hormones.
It will settles down in time..

I remember that time in my life.

This is normal.

You're old enough to babysit now. So why not take a course in babysitting, then find work babysitting the babies you want to be near.