You could fiddle with the key bindings in OG Doom using the setup program, albeit not in game, which is the fate that may have befallen you. OG Doom’s default controls have the arrow keys for moving forward and backwards and turning, and you strafe by holding down Alt and using the arrows or via the undocumented at the time period and comma keys (or < and >, if you care to think of it that way).

It was pretty common for deathmatch nerds to make left and right or possibly A and D the strafe keys, and use the mouse for turning. Pushing the mouse fore and aft also moved you forwards and backwards which was nonsensical in hindsight, but vaguely understandable for a game that has no vertical aiming. A popular hack at the time was a mouse driver patch which essentially nullified your mouse forward and back movements to near-zero while leaving left and right intact, so mouse users wouldn’t be always be backpedaling off of ledges or mashing their faces into walls inadvertently.