Irs cannot tell me whether or not my return has been accepted & my state return has been accepted but needs further review...why? because i mailed both rather than efile

could you have mailed both in the same envelope?.  the state does not forward federal returns to IRS and vice versa.    go to irs website and see if you can get a transcript of 2018 return. if there's nothing there, then the IRS never got it. refile asap