1) do not look at Petfinder or other rescue sites when you cannot
A) currently afford (time- or money-wise) another animal
B) are already feeling a bit down
it will NOT cheer you up.
2) the next horse you get when you can get one must be a good "husband horse"
3)
a 13 hand slightly gentled Mustang stallion is NOT a good "husband horse" for a 6 ft. tall beginner even if he is blue roan
4) your next project horse is many years from now. Really. Remember this. Even if this is a blue roan Mustang. And nearby.