so i tried to start my car, and it cranked&cranked&cranked, and i kinda grunted and died, and it won't start and i don't know why?

Start by posting specs on your car, the 1st thing to check besides gas gauge will be spark. Take an old sparkplug and pull a spark plug wire off stick the plug in it rest it on the manifold and have someone crank it. Let us know what u find. my bad didnt read your specs, could also be neutral safety switch, but find out if u have spark 1st.

do you think i could test it with a plug from my lawn mower, i dont have any old car ones laying around?

sure, or pull one of yours out.