Hi Sara,
Thank you for contacting us. While I'm not sure what's happening here, it is highly unlikely your account was compromised. The first thing to be aware of here is that if someone did gain unauthorized access to your account, the last thing they would want to do is draw attention to it create a single record where you would notice they had access to it.
Also, the only way to access an mSecure account is to sign in to the account in the mSecure app on an iOS, Android, Mac or PC. When this happens, you receive an email telling you your account was signed in to. The first thing we need to do here is check to see if you have a sign in notification in your email. Do you see any emails sent to the email address you use for your mSecure account?
Sara