I filed my tax return Mid-Feburary and have not gotten it. I checked the IRS "wheres my refund" tool and it does not have any information. What can I do to get my refund?

I even tried to use all the different filing statuses, checked the refund amounts  - $1 (thinking there may have been a rounding error) and nothing worked. it is as though they do not have my return at all :(