Rows 1-3 are missing on my spreadsheet, but when I click "unhide rows" they don't reappear

I'm not sure how this happened, but I have three sheets in my Excel document. On all three, Row 1 is the title and 2-3 are descriptive information. On the second sheet, for some reason, it starts at row 4, and I cannot get 1-3 to be visible again. I tried to un-hide cells, but nothing happens, which indicates to me it's a different problem and they're not just hidden. When I attempt to insert new cells above row 4 and re-type the information, it just adds cells BELOW and continues to start at row 4.

Any input would be helpful. I'm on my work computer, most recent Windows version, Office 365.