PIVOT Help

I don't know why but the PIVOT function escapes my comprehension.

All I am trying to convert the following :

DateResponseCount

2012-03Sent50
2012-03Opened36
2012-04Sent45
2012-04Opened15

into the following :

DateSentOpened

2012-0350 36
2013-0445 15

My code is simplified to be easier to read, but is essentially the same.

WITH my_CTE ( Date, Response, Num) AS
(
SELECT 
	Date,
	Response,
	Num
FROM TABLE_IN_MY_DATABASE
) 

SELECT Date,
	[Sent],
	[Opened]

FROM ( SELECT Date,
		Response,
		Num
		FROM my_CTE) A
PIVOT ( SUM(Num) FOR Response IN ( 
				[Sent], 
				[Opened])
) AS unpvt

With said code I end up getting :

DateSentOpened

2012-0350 NULL
2012-03NULL 36
2012-0445 NULL
2012-04NULL 15

Thanks for all the help.