Hello I have this Ancient coin which I am unsure whether it is Roman or from somewhere else. The weight is around 2 grams, and the diameter is roughly 16mm.

On the obverse there appears to be a woman with a bun of sorts.

On the reverse there is a horse standing with one of its front legs lifted facing left on a line, the letter B or R followed and preceded by other letters below the line.
here is another photo of the reverse:
