CPU utilization alert is not working for AWS CloudWatch datasource

I have created a panel for CPU utilization and data is fetching from CloudWatch datasource.
I have created a alert if cpu usages reached 90% then we should receive email notification but I am receiving email in every 5 minute even there is no cpu usage more than 80%.

It is fetching those instances as well which has been terminated in a past. Suppose I launched EC2 instance 11hrs before and I am fetching instance based on time range last 12 hrs, will get all terminated instance details along with cpu usage. Is there any way to get only running instance cpu usages?

3rd point is, in email notification I am not getting proper instance details for cpu usages instance. Whatever message I am passing in alert, same I am getting as a output in email. How we can get instance id or name in email notification along with cpu usages?