High temp low oil light came on but oil was fine now motor has a knock

Hi, my 2003 mercury mountaineer was having the
hi temp low oil light coming on, but the oil was fine,
it had a little bit of a knock  well i trued to drive it
home cause it wasnt hot, about 5 miles from my
home the knock got louder but everything else
seemed fine then the engine died and i cant figure
out how to fix it, and im to scared to start it back
up but it will start, im a female that doesnt know
much about cars and its my only transportation,
someone please help