Hi, this query may get you some of what you are looking for (fill in your db name):

--Redo Queue KB

--Total number of kilobytes of hardened log that currently remain to be applied to the mirror database to roll it forward. This is sent to the Principal from the Mirror.

--Log Send Queue KB

--Total number of kilobytes of log that have not yet been sent to the mirror server.

SELECT [counter_name] as CounterName,[cntr_value] as CounterValue

FROM sys.dm_os_performance_counters

WHERE [object_name] LIKE ('%Database Mirroring%')

AND [counter_name] IN ('Log Send Queue KB','Redo Queue KB')

AND [instance_name]='myDatabase'