Bush's low numbers right now are due IMHO primarily to high gas prices and the MSM campaign against the war in Iraq. I think there is also a component to the numbers the media probably don't even know about, which is conservative unhappiness with Bush over his refusal to veto bloated spending measures and continued fighting of the WOT by Marquess of Queensberry rules.
Could be.
Again, Bush is tackling the big issues and seems less interested in the polls than his predecessor. And you are right - he faces concerns on the right as well as the left. Immigration, spending, etc.