Truck won't start

After driving my mom to Walmart I parked my truck
the next morning it wouldn't start. I didn't hit
anything or get hit. I even gave my cousin a ride 10
min after but when I got home I sat in the truck for
like an hour with the key in the ignition for like an
hour waiting for rain to stop. Idk wether it was on or
off. I was too busy on the phone. We had just
replaced the alternator a week before. N now we
replaced the starter n nothing