I am not entirely sure of all details regarding its orbit, but looking at its trail it seems to deviate away from the planet Earth instead of towards it. What happened to it from around mid december 2023 to now?

More details:
https://eyes.nasa.gov/apps/asteroids/#/watch/2024_am?time=2023-12-20T20:59:29.669+00:00

Normal. It's outside the Earth Moon system by a considerable margin, so the gravity well is far too weak to affect the trajectory in any meaningful way.

What you have to understand here - the ROTATION of a moving body greatly affects it's perceived motion across time space. Try spinning a coin on a flat surface, the spin hugely affects which way the movement across a distance behaves.