Alexander the Great, Babylon mint (?) [opgelost]

 Dear experts,

Please help me more precisely determine the time and place of minting of this coin.  Its diameter is about 12 mm, and it weighs 1.90 gr.

I purchased it as a ½  drachm of Alexander the Great, but now I have some doubts.

Thank you in advance.

Best regards

Uri

The only coin I could find on Numista that is close to yours is this one: N#403226. It has the same M that yours has on the reverse but I don't this yours is this one because the size is so different. 

Thank you!