Nested foreach inside a while loop, array is not an array after first while

I have a while loop with a nested foreach loop, after the first while loop is run the array inside the foreach loop is being unset (or at least ceases to be an array).

Where I'm headed is an array of data for a bar chart which shows every day since a start date and the number of clicks by type (8 types) on each day. So I'm calculating the number of days from the start date to now, and for each day it checks the first array to see how many, if any, and what types of clicks there were on that day.

Here's the relevant bit of code...

$i=0;
while($i<=$numdays)
{
echo $date2->format('Y-m-d') . "<br>";

foreach($clicklist as $key => $clicklist)   {
      if ( $clicklist[clickdate] === $date2 ) {
      echo $clicklist[clicks]." clicks on ".$clicklist[type]." on that date<br>";
        }
       }

$date2->modify('+1 day');
$i++;
echo is_array($clicklist) ? 'Array<br>' : 'not an Array<br>';
}

$numdays is the number of days from the startdate to now (needed for one of the chart variables, $date2 is the startdate and $clicklist is the array of clicks/dates/types from the db. All the random echos are just so I can see what's going on - or not as the case may be.

The while loop works fine is isolation, the foreach loop also works fine outside the while loop (using a static date in place of the variable), but of course that's just a one time run.

From the manual, foreach resets the pointer back to the start automatically, so that's not an issue.

I'm missing something obvious I'm sure.. any guidance much appreciated.