I filed on 02/07/2018 and it shows that it was received by the IRS its not approved yet . I already received the State refund. is there something wrong with federal?

Once your federal return is accepted by the IRS it can take up to 3 weeks for the return to be approved.

If you wish to track your return please visit the Where's my refund website here- https://www.irs.gov/refunds , this will allow you to see the most up to date information on when the IRS will release your return.