An account has been opened at a betting site using my email

Email accounts get compromised every single day... by the 100,000s.
probably not a single person here has not had an email account sometime in their past hacked.
There is safety in numbers. There are so many that are on the dark web, that the likelihood you will suffer from it is very small.

The best email security - Have multiple email accounts.
1) Work email. Never use your work email for anything other than work. PERIOD.
2) "Internet email account" - like the name implies. Use it for everything you do online, example the email you list for this website. Amazon, Facebook - whatever you do online. Ideally, you never really use it. You never send emails to anyone, unless replying to one of those sites.
3) Your personal email. Used for non internet connections. Example - what you give a doctor/bank etc. And if you use email for personal reasons, this is the one you use for that. You do NOT use this for internet commerce.

If you do this - you will be astounded at the shear level of advertising and spam your #2 email gets. Even if you have never sent an email.
And your business/private email will get very little. And it will be safer.

Good advice.

E-mails written on the job (on a company or state-owned computer) are regarded as "belonging" to the company if push comes to shove. Don't let it. Use your work computer for work only. I never even logged into DP at work; I always assumed that somebody somewhere is monitoring.

When I was growing up, we had two phone lines. Nobody had the private line number, nobody. I wish I'd thought of this earlier in my e-mailing life (!!), but I do now have an e-mail for commerce only. I do have IRS and other important stuff sent to my personal e-mail, though. The reason is that I rarely go to that second account and end up deleting 200-300 messages at a time from Bath and Body Works. So many companies send daily e-mails!

I have three email accounts. One is my SpamAlot account and I deleted it's in messages by the truck load.
The other is my personal account and I keep it filtered pretty well.
The third is a disposable system.