I've taken multiple hiatuses before. What matters is for your own health and well-being. Don't worry about posting or being online (in some cases that is just added stress). Do inform your readers that you're taking a break and if you know how long it will last, tell them that as well.
You don't need to tell the exact reason if it's personal, just the information of a break is enough. Since most readers are in the app (I assume) tell them via an author's note and post it on your profile.
If you use a lot of social media and want to take a break there too -- write hiatus somewhere on it, so people are aware you won't be as responsive as usual.
I wish you all the best!