3% would actually be pretty good, that likely would mean Trump would win the electoral college, polls only measure popular vote support and most polling experts say because of the way democrats run up huge margins of the popular votes in states like California and New York, Trump could lose the popular vote by as much as 4% and still win the election.
Read this one real close! Trump is AHEAD in the midwest, think like Wisconsin, Michigan, Ohio, Iowa. If Trump sweeps these, the election is over, (unless Biden somehow pulls a rabbit out of his rear end and wins Texas or something equally as unlikely)