Use a site monitor to send you an email as soon as you’ve got the website down, or back up again as well. There are many websites that do that, just search “website monitor”. There are paid and free options. One free option up to three sites is Pingmonit in case you want to try it. The alternatives are, while no one complaints or you don’t visit your website, you will never know of what’s going on.
https://www.pingmonit.com/ is one example of free monitor up to 3 websites.