To preface this, I'm trying to get into orbital mechanics (and am a complete beginner if you can't tell after this post).

Say I was on an EVA from the ISS, and decided to take a tennis ball with me. What would happen if I decided to aim it at the earth and throw it as hard as I could?

Newton's first law states that an object will stay in the same state of motion until another force acts upon it, so surely it would continue heading towards the earth? Relative to me, the ball would keep speeding off into the distance until I lose all visibility, what happens next? Does it somehow cancel all forward velocity and decide to follow a lower orbit? or does it continue to move forward and enter the atmosphere?

Surely it can't just keep going forward because that would make space travel a ton easier. My best guess is that as you are transferring energy into the ball, it would move to a lower orbit, as everything in space follows an orbit (?), but I am not sure how it would look like relative to me.