In late summer 1862 the Federal army in the West was also having trouble What was the root of this trouble?

In the summer of 1862, an American civil war was fought which lasted for just a day. This battle proved to be the bloodiest day of the war and it was recorded that there were many casualties in such a short period of time which led to the war being called off on the same day. General Lee who led the troops for the Federal army in the West had about 2,108 of his soldiers killed and 9,549 wounded. This made him withdraw back to Virginia and his opponent McClellan who led the Confederates was declared the winner although there was no true winner as both suffered devastating casualties.