Well here u go, mate by king and rook, looked hopeless. ;)

I am black.

Can someone tell the opening i played? Just mention i am not aware.

Before your second move I think that the opening had its name. 2..Bd6 is something like "novelty", but many would call it by its true name, "a mistake". But ok, let's continue.

well, I don't have many words for the part usually called "middlegame" because I don't understand it. Also I don't understand some parts of the title of the topic, namely "attack", then "counterattack" and also the one about the "epic win".

Actually what white had to do was avoid the back rank mate until the 2 connected g and f pawns support each other. Then white wins. Maybe your opponent was under time pressure. I have done this many times to others too

Hope this helps!