sent emails not from me

It sounds like your email account may have been compromised, especially since you are seeing sent emails that you did not send. Here are some steps you can take to address the issue:

1. Change Your Password: Since you've already changed your password, ensure that it's strong and unique. Consider enabling two-factor authentication for added security.
2. Check for Compromised Account: If you suspect that your account is still compromised, follow the steps in the article on responding to a compromised account. This includes checking for any unauthorized forwarding rules or delegates that might have been set up.
3. Wait for Sending Limits to Reset: If you have exceeded your sending limit (which is 10,000 recipients per day in Exchange Online), you will need to wait for 24 hours before you can send emails again.
4. Scan for Malware: Run a malware scan on your devices to ensure that there are no malicious programs that could be sending emails from your account without your knowledge.
5. Contact Support: If the problem persists, consider reaching out to Microsoft support for further assistance.

By following these steps, you should be able to regain control of your account and prevent further unauthorized activity.

References:

• Fix NDR error "the sender's submission quota was exceeded" in Exchange Online
• Responding to a compromised account