I planted a Shumard Red Oak two weeks ago, and the leaves are turning brown?

I know how frustrating it can be for a new tree to flash brown. It sounds like your tree suffered transplant shock, which is no surprise, as hot as June was this year. Usually planting a tree too deep causes problems over time, after the tree becomes established. However, there is the possibility that the tree's root system, having been planted too deep, did not drain properly and became anaerobic. This could cause the leaves to brown out. I would do as you suggest: Dig it up and replant it, but only after ascertaining that the tree isn't completely dead. There would have to be bud swell on the tree (evidence that a new flush of foliage is emerging).