I have made a tactic which happens go unbeaten through a whole season with Ispwich wining most stuff that was available, but my game crashed and it deleted my fm for about a month so I could not remember what the tactic was
you would not have lost your tactics folder mate, the tactic will still be there! just arrange the tactics in date format and see what was the last one you used (and was saved)
it will be there 100%