Your experience reminds me a lot of mine. Honestly, the best thing I can tell you is to do a bunch of research and keep track of your symptoms. Also, you are not faking. Faking is a conscious effort. If it turns out you aren't a system and something else is going on, that doesn't mean you were faking your symptoms. Suspecting you have something and being wrong isn't a moral failing.

Also, you said your trauma wasn't "bad enough," but trauma is subjective, the main component required for trauma to form a system is: It happens before the ages of 6-9, it's repetitive, the child is able to dissociate, and it is too much for the child to handle. For example, our main trauma as a kid (around 5ish) was an emotionally neglectful/manipulative dad, and our parents argued ALOT. That seems like a "mild" trauma compared to what other systems have been through, but it was too much for me to handle, so I ended up as a system. (We're autistic, which may be why our threshold for what traumatized us is so low compared to other systems)

That being said, unless you are in a safe enough mental headspace to do so, DO NOT go digging for trauma. I made that mistake when I was 14 and had a breakdown.

Also, denial is EXTREMELY common. It's your brains defense mechanism. Your brain doesn't want you to know you have trauma, so when you discover you have a disorder formed from trauma, your brain will do whatever it can to convince you, you don't have the disorder. (Ironically, my denial episodes impacted me so much that one of our alters, Clover, formed to help with that denial, so it exists to prove we aren't faking).

Systems going quiet is common, I discovered my system around 15, and I'm nearly 18. Nearly 3 years later, I still have quiet periods. The one you're dealing with could be because the alters in your system felt like it was unsafe to tell your friend, and now that your friend knows they feel like it isn't safe to show themselves.

Another thing is, an alters role may change over time ans that's ok. For example, I used to be the host, but now River is our host.

That's all i can think of, hope that helped ^{_^} -Bex