Hi, yeah it is very common are certain types of play, particularly if it has been very intense.
It’s known as drop and it’s essentially where all those chemicals that made you feel euphoric leave your body. It can happen straight after or it can take up to a couple of days. Some people find it doesn’t happen every time and some people find that the more you get used to doing the activity, the less the drop hits.
Different things can help so it is about figuring out what works for you. It could be cuddles, reassurance, quiet time, some time and/or space to process (talking hours more than days here), food and drink (although go easy on the sugar and alcohol, but a mix of protein and carbs can help), talking to your partner in the few days after, and generally whatever you might do for some self care, so things like little treats, having a nice bath, watching your fave movie/TV, taking a walk, listening to your fave music.
It is most associated with bdsm play, in particular submission, and there are lots of articles online about sub drop. However, it can happen to anyone after any type of sex and even after non sexual things as performers and athletes can often feel it. It can also come from things like finishing exams or coming home from holiday.
My best advice is just to be nice to yourself when you feel like that and know it will pass quickly