We'd need better pics of both sides to judge one way or the other, but there are some things you can do if better pics are impossible.
Are the letters "WRL" stamped into one side or the other? Or a large letter "R", or the word "COPY" or "REPLICA". Any of these are stamps applied by souvenir replica-makers to their replicas. If any of these marks are present then your coin is absolutely 100% not genuine.
If your coin passes this simple test, try taking it to an expert. London has several dealers that frequently deal in ancients ,such as Spink, and Baldwins. They should tell pretty quick if your coin is fake or not. You'd also be much better off selling a genuine coin through their auction than putting it on
ebay, where most people will assume it's fake whether it actually is or not.
You could also try the British Museum; their experts are always happy to help out members of the public with identifying their finds; they should be able to spot a fake.
Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis