Why Do I Feel Weak, Tired, And Have A Fast Heartbeat All Day After Ejaculation Until I Sleep?

Hello! Why Ejaculation causes me tiredness and loss of energy that I can t be comfortable all the day? I know people who don t have the same problem, also when I sleep everything goes good and I recover my energy back.. but the problem is I can t sleep as fast as I can after it.. so I suffer a lot from being in a state of weakness and I feel like my heart beats faster all the day.