Create report compareing 2 Sheets

Can you please help me with some ideas on following:

Every day i create a attendence sheet with names, who was attening a club the last 21 days.
I need some kind of report showing who is in Sheet1(Today) and not in Sheet2(Yesterday)="new people" and who is in Sheet2 but not in Sheet1 (people that stoped attending, droped out the list).

I tryed with "countif" and "Vlookup" but have to change the formulars on two sheets every day and i would rather like to leave leave the Sheets untouched.

Any ideas?
Thanks in advance