Composing difficulty

Hey there, I had an idea pop up in my mind, and I wrote a short motif and I plan to extend it into an orchestral piece. But the problem is: this motif seems really familliar to me, I don't know why, and I think I've heard it in a classical piece somewhere. Can anybody tell me if this is/is simmilar to a classical piece? I just want to be somewhat original. Thank you :)