Hello Rayna, welcome to the site! There's lots of nice threads to join on different topics, and looking back through previous threads is a great way to find lots of useful advice and get a feel for other people's approaches to PhD studies.
No idea how many users there are! There's a smaller core of people who are here quite a lot, and then a lot of people who pop in with specific queries or problems they want advice on. That can sometimes make it seem like a PhD is very stressful, as so many people come here specifically when they have a problem, but we do try to talk about the good side of PhDs as well!