sql count for a week

I have a query where I am counting number of session per weekdays and this part works.

What the problem is when the date is passed I want to check the week and count the number of session in that week, instead I get the number of sessions for that day

Select WeekStart = convert(varchar(10),dateadd(week, datediff(week, 0, SU.sessionStart), 0),105),CountID = Count(S.sessionKey)

			FROM SessionUnit SU
			INNER JOIN Session S on S.sessionKey = SU.sessionkey
			INNER JOIN product P on p.productKey = S.productKey
			CROSS APPLY (
			    SELECT item AS SPLITLOCATIONKEY
			    from DelimitedSplit8K(S.locationKeyList, ',')
			)as ca
			INNER JOIN location AS L2 ON CA.SplitLocationKey = L2.LocationKey AND (L2.locationKey in (228,260))
			WHERE  su.sessionStart >= DateAdd(day,45,dateadd(day, datediff(day, 0, getdate()), 0))
			AND su.sessionStart <  DateAdd(day,91,dateadd(day, datediff(day, 0, getdate()), 0))
			AND datediff(day, 0, su.sessionStart) % 7 not in (5, 6)
			AND p.productKey = 2  and SU.instructorKey = 13879
			and convert(date,SU.sessionStart) = '2015-05-13'
			GROUP BY
			 dateadd(week, datediff(week, 0, SU.sessionStart), 0)
			 --HAVING COUNT(S.sessionKey) >= 9

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