I found out why my tire went flat. I did what I had to do to get the tractor off of the side of the hill that it was on. I didn't feel comfortable leaving it where it was with how I had to jack it up.
It took 2 plugs to get it to hold air. Now that the tractor is back on level ground, should I take it to the tire store to get a patch put on the inside? Did I make a mistake by plugging it? I don't feel like the plugs will hold.