The trouble is that only someone on the flight, or a maintenance engineer called to inspect the aircraft afterwards could tell you whether that landing was normal, firm or heavy. Certainly if the landing was too heavy the aircraft will have gone nowhere afterwards without a maintenance inspection. Firm landings are common and can occur for a number of reasons. Heavy landings are quite rare.
The landing gear will take a great deal of abuse before there is any danger. You're far more at risk is any misstowed hand luggage decides to fly around.
Did the aircraft burst any tyres?