With whole pitch press and normal or attacking mentality, you tend to score a lot more and also concede about twice of what you would normally concede. This probably due to the fatigue factor. Also, after the match, your player condition will be very low and sometimes there's not enough recovery time, especially if you use whole pitch press every game.

In reply to the thread topic, did you check your opponent's starting XI? Are the starting XI quality lower or higher than yours? Remember, a team could have low squad quality but it is contributed by 1-2 star subs & reserves.