I was in this position in a recent game...Can anyone suggest the next best move?

I played 6.Nf3, thus targeting both the e5 pawn and the threatening d4 knight.

The previous moves were : e4,e5/Bc4,Nf6/Qf3,Nc6/Nc3,Nd4/Qd3,Bb4...

i think Nf3 is the best move but no matter what white is in little trouble not losing but not winning

The real question is - why is your queen on d3?

Is it because you earlier played Qf3? If you did, don't do it in the future. It's bad.

I agree. The problem is not in the given position, but back when you did 3. Qf3. The opening is not the time for mating attacks. Use it to develop your pieces and control/attack the center.