Everyone will be laughing at something that you don't think is all that funny today, but try not to get grumpy about it. If you feel like you're missing out on the joke, don't let it unnerve you or weaken your self-confidence. You're just a bit out of synch with other people right now, mostly because you've been so wrapped up in your own stuff: and rightly so. It's just going to take a little bit more time to get back into the swing of things, so be patient with yourself.