Originally Posted by boydster
Patience. At 7 hours, it's normal for the yeast to still be in the lag phase. As far as the OG reading goes, +1 to unionrdr's suggestion that your top off water probably just didn't mix thoroughly - don't sweat it. As long as you used all the extract and got your water volume correct, your actual OG should be exactly what the kit instructions say.
The yeast may be at the bottom now (well not all of them- they are microscopic and so you only see them when there are tons of them, but there are still plenty in suspension) but they know where to find the sugars.
Walk away for at least 24 hours, keeping the beer temperature at 66-68 degrees if at all possible.
It will be fine, I promise!