If you are the site collection admin and if you received this email "You are receiving this e-mail message because you are an administrator of the following SharePoint Web site, which has exceeded the warning level for storage..." No need to Panic. :)
You received this email because the site collection quota is nearing your total storage.
Steps.
- Go to Central Administration
- Navigate to Sitecollections
- Click on Configure Quota and locks
- Change the storage size
Happy Share Pointing :-)