I have actually NEVER been told that I look like a celebrity.
I have a crooked chin similar to Drew Barrymore (ever notice the crooked sideways smile? I have that) but I don't think I look like her at all. I'd be happy to know if anyone could make comparisons...
That's me on the left The handsome dude on the right is my BF. Who gets told he looks like Jack Black a lot! I personally don't see it but it's happened enough that I guess there must be some sort of similarity. I guess I can see it in the eyebrows.
The first celebrity that came to mind after seeing your photo was Amanda Peet...