Is it normal to feel like this in intense sad situations ?

So the thing is, when i'm in a really sad situation such as a funeral or the bride leaving after marriage (even if they are my own people), everyone around is like crying and sobbing but i dont feel a thing. Rather i find it really hard to hold back my laugh (I've never laughed though) . I do hide my face and smile. Is it normal? Should i do something about it?