I accidentally deleted a lesson, help please

I sure was hoping.  I had two section twos in my course as I was trying to save time and I had duplicated a course, I went to delete the old lesson 2 and accidentally deleted the one I just spend a day on....I was watching the box in the bottom left but couldn't figure out how to stop it.  Why is there not a warning message or something?  I am not a new user...this makes me very sad.  I thought there was hope when I saw someone post about deleted content, but that seems to be for a full course....can we flag this again?