Cannot select a node here: the context item is an atom

Hello,
I'm using XSLT/XPath 2.0 and am stuck on a very basic problem again. 
All I want to do is nest my for-each loop inside another loop so that
the inner for-each loops executes x number of times.
To be more specific, I'm creating an HTML table with dates running
down the left column and corresponding values in the rest of the
cells.
So I have date range: $date1 to $date2
I calculated the number of days between the two: $dayCount

<xsl:for-each select="1 to $dayCount">
   <xsl:variable name="day" select="($date1+
xdt:dayTimeDuration(concat('P',position()-1,'D')))"/>
   <tr>
     <td>
       <xsl:value-of select="format-dateTime($day,'[Y,*-2]-[M,2]-[D,2]')"/>
     </td>
     <xsl:for-each select="my/xpath/query[@day=$day]">
       <td>
          <xsl:value-of select="."/>
       </td>
     </xsl:for-each>
   </tr>
</xsl:for-each>


The inner loop gives me this error:
Cannot select a node here: the context item is an atomic value

Could somebody kindly let me know how to do this?  It's clearly stated
in the documentation that I can't do it this way (nest node loops in
atomic loops), but I don't see a workaround.

P.S. Also any hints if there is a better way to do that outer loop
would be appreciated as well.

Thanks!