There is no need to get worried if you have forgotten to save your excel file. Because you can recover your unsaved excel file. Steps are given below, just follow them step by step:
First, you have to open your new excel workbook
Then, click on the File option
And then, you need to click on the open option and then the Recent option.
After then, you will see the Recover Unsaved Workbooks option in the right bottom corner, simply Click on it.