Over a few days last month, I entered ALL of my return data. Today, ALL of that saved data is gone. I spent hours entering all that data and now I have to start over???

I had completed all the sections for my income, expenses, mortgage interest, charitable donations, etc. but when I logged in today to complete my return, *everything* I input is gone. Only my basic personal data is saved. I spent hours entering all the information over the course of a few days. I logged in today to finalize my return but everything I had already entered is now gone as if I did nothing previously. Now I have to regather all of those documents, start over and re-enter everything???