Filing your tax return and paying your taxes are two physically separate things. You may have paid your taxes as evidenced by having a cancelled check. But that does not mean you successfully filed your tax return. If you e-filed, check the status of that e-filed return. ( don't know how to do that with a state return)
More than likely there was a problem with your e-filed return and it was rejected by the state. If that's the case, then you have to choice but to print, sign and mail your 2018 state return now. (You can not e-file a prior year tax return.)
