Session Problem

 Hi Can someone point me in the right direction please, pulling my hair out, the joys of a newbie

 If I type this:
Response.Write(Session(Session_LoggedInEmail))
I see my email address when I log in but I want to use my email address in the WHERE; I just can get it to work, anyone see what I have done wrong?
 This is what Im trying to achieve
Session(Session_LoggedInEmail)  = @email_address
 This is the code Im using below:-

 <asp:SqlDataSource ID="UserData" runat="server" ConnectionString="<%$ ConnectionStrings:TriSysV7_Live_test %>"
                        SelectCommand="SELECT [email_address], [divisions], [keywords], [type], [user_added], [removed] FROM [txtByEmail] WHERE ([email_address] = @email_address)">
   ...