I am about an eighth Native American, also from various sources (An old Saponi tribe in North Carolina and Cherokee from Northeast Georgia, Alabama, and South Carolina), but even Gedcom gives very little Native American. Instead, they seem to lump it together with much of the Asian and Polynesian -- all of which comes to about 10 - 15%. Gedcom, while a good number of their tests are more accurate (so I would give it a try if you haven't because it can be helpful and has more tools for you to use in general), goes in the opposite direction of Ancestry -- I normally come up with being about a quarter Romanian, a quarter British, a quarter German, and a quarter Norwegian. Quite odd. Also give a 23andMe a chance if you have the time and money -- much, much more accurate than both.