Can I use "my day" to refer to a period of more than 24 hours? Let's say I worked non-stop for 30 hours, could I refer to this period as "my day"?
From a dictionary, the only two usages I was able to find were:
You could call it your day but you might want to consider calling it your work day.
The standard astronomical day is based on the rotation of the earth on its access and takes about 24 hours (at least on earth).
By convention, most cultures count the start of a day immediately after midnight. However there are other conventions of when a day starts (such as at sundown in Jewish religious tradition).
People routinely say my day starts with getting up in the morning (6AM? 7AM? 11:59AM).
Similarly, people describe their day in terms of their work.
My day began with the first angry customer, and didn't end until the last satisfied patron left and I locked up.
So the start and end of a day are anything but fixed.
If your work day is more than 24 hours, there is no reason you could not describe it as a day. But, unless you give it a context, no one will understand. So, it would be fine to say
My day runs 30 hours straight. But the upside is I only work two days a week!
Probably it would make more sense to say
My workday is 30 hours long. Then I am off for 54 hours and start all over again.
