Group By Question

I am trying to write a query to return how many items were sold in particular months. Right now its returning the same item multiple times per month.

select distinct itemID, sum(AmtSold), yrmonth
from inventory
where YrMonth between 201105 and 201108
Group by itemID, yearmonth, AmtSold
Order by yearmonth , productid

I just want each ItemID returned once per month with the Amtsold summed for the whole month per item.

Result I want:

item id  AmtSold  YrMonth
123       230     201105    
456       150     201105
123       175     201106
456       122     201106