When asked whether you are in the US still or not, this refers to whether you are still studying/working in the US as of the moment you are filling your tax return. If you went on a vacation somewhere but you will come back to the US in approximately 2-3 weeks then you can still answer 'Yes' to that question.
If you returned to your home country and do not plan on returning to the US for a couple months, then it is best to select that you are no longer in the US. That does not mean that you will not return to the US.