My left big toe nail has a crack going from one side of the toe to the other. there is some discoloration on the nail itself and it seems as though its going to eventually fall out. i am unaware if there was trauma to the nail?

You might want to see a podiatrist to take a look at it. But, most times if you lose a nail, it does grow back. It does take a while-it is unclear from your description how low on the nail it is breaking so, if you don’t lose the whole nail it will grow back faster. If you have a fungal infection of the nail causing the break, a podiatrist can diagnose and treat this. Good luck to you!