I agree with brass napoleon - Gettysburg was not a turning point at all. The strategic stalemate in the east was no more changed by Gettysburg than it had been by the Union defeats at Chancellorsville or Fredericksburg. The rest of the war, and the downward spiral of Confederate fortunes in the west, continued unchanged. The side that needed a turning point had not gotten one.
Not sure I would call the Seven Days a turning point either, but it was more significant. After the defeat of the hastily formed volunteer army at Bull Run, the Union spent most of a year organizing a force capable of taking the Confederate capital and dealing a crucial blow to the rebellion - and it failed to so. The Seven Days set the pattern for most of the war in the east and established the paradigm that Grant would identify in 1864 - "You fellows worry more about what Bobby Lee's going to do to you....."