I don’t know what this is, or if it is ancient, but I have some thoughts.
The figure at the left is wearing a Corinthian (Greek) helmet, pushed back over the forehead, like this:
That’s one of the common depictions for Athena on coins and elsewhere, as the Greek goddess of warfare (and wisdom). She was also the protectress of various Greek cities, and especially Athens from which the name likely derives (or vice-versa). I can’t see the facing figure as having a Greek helmet style, nor a Roman one. Also, at the top of the reverse, I can see the letters ‘Ο Γ Γ’ (or possibly ‘O T Γ’), which would be consistent with the ancient Greek alphabet. Likely this will be an abbreviated form for the name of a place, authority or person (including the possibility of a ruler) but it’s not something I have seen before. The ‘E’ at the left would also be within the ancient Greek alphabet and might be a mintmark. The other characters I’m not sure about.
Ancient Greek bronze coins can be commonly found in sizes between 30-40mm and occasionally beyond, so I don’t have a problem with the size and weight. Some of the larger ones are often referred to as ‘medallions’ but in many cases there’s no doubt that they were coins… only doubt about whether they commonly circulated as ordinary currency.
I use the word “Greek” in the sense that it applies to the Greek Empire in general, its related Kingdoms and its Greek-speaking colonial territories which stretched far and wide in ancient times.
The decline of Greek influence began with the Roman victory at the Battle of Corinth in 146 BC but many areas were allowed to retain their Greek heritage under Roman rule for some time. Coins with Greek symbolism or with a combination of Greek and Roman imagery are not uncommon after the Roman victory at Corinth, but I can’t see the figure facing Athena as Roman.
IF this is an authentic ancient coin (or medallion), my guess is that it’s from some far-flung part of the Greek Empire as an obscure local issue and that the figure facing Athena relates to the original heritage of that territory, or a local King under the Greek umbrella. I could see the helmet style as possibly being from the Middle East or Near East. Persia, for example, but there are other possibilities. Until about 1 BC, the Indo-Greek Empire still existed in Afghanistan, parts of Pakistan and NW India, undisturbed by any Roman conquest or interference.
I haven’t seen the ‘sow with piglets’ before, either. It might be symbolism for prosperity or ‘benevolent mothership’ under Greek rule (my guess).