I was in one a while ago. I endured torture. I hadn't access to my mobile device, I was forced to a dumb day routine in a fucked tiny space with a bunch of others, I watched people on meth, people shitting themselves, growling under my bed because why not, and other things. They said it was going to be only a few days. It was weeks. By the end of every day I was feeling worse and worse, on the edge of insanity. At the end of the first week where they refused to give me sleeping pills and didn't sleep I started to lose touch with reality and laughed on nothing, hallucinated people, hallucinated the toilet smiling at me and I kept laughing on that, later I ended up being angry for no reason and hitting walls , almost broke my knuckles. It was the worst fucking experience in my life. It was worse than prison. They didn't even give proper food: just a slice of small empty bread with 5g of butter. It was utterly fucking disgusting. I could go on and on and on what happened there. By the end of 2 weeks I completely lost it, which was their exact goal: that way they could prescribe drugs and force me to pay while losing my brain. They wanted me locked away forever. They tried to prove I have schizophrenia. (They failed because my family got a medical lawyer, who ended up almost suing their asses, which made them suddenly not think I have any illness at all besides depression). It was the worst.
I hope your stay will be not as bad as mine was. Sending hugs.