I'm bored and I don't feel like doing anything about it so I guess I'll take this opportunity to ask some of my questions.
1. Is it normal to have conversations with people in your head? I do this a lot. I really "talk" a lot about my problems. They usually don't respond, but sometimes they do. They rarely help me though. They just listen.
2. I feel like I have no friends or like they're all against me. If they don't tell me something that they all know, I feel like they all have these plots against me to humiliate me or make me miserable or something. I get these ridiculous ideas in my head and fully believe them for a few days and get all depressed. I don't tell my friends about them of course but it makes me feel like an alienated loser. They always do things without me while I sit at home pitying myself. I want to ask them to do things with me but I feel like they don't want to be with me and I don't want to force them to. I've told two of my best friends about this and they told me that they love me and stuff but I can't bring myself to believe them no matter how much I want to. I made them think that I believed them though, so as far as they know everything is fine.
3. I sometimes see or hear things like a dog driving or people yelling at me. I've been having crazy dreams for the past few months, too. Also, is it normal to start dreaming before you fully fall asleep? I don't know how to explain it but sometimes I notice I'm dreaming and I'm still awake so my surroundings go all weird. It's really bad when it happens in class because then I start reading or hearing fake information mixed with real information and it gets me confused when I actually am awake.
4. I can't seem to let go of things that happened in the past. I know I should and that it will really help me but I can't. I miss how my life used to be but there's nothing anybody can do about it. I fully realize that there's nothing anyone can do but I still want things to somehow go back to how they used to be.
5. I want to go to therapy again because I feel like I'm totally losing it and I need someone to listen, but I don't want my mom to know. She thinks I'm better now and I don't want to burden her with the knowledge that I'm not. I'm fifteen though, so it's not like I can just waltz up to a therapist and expect free help. But I also feel like maybe I'm making these things up or that there's nothing wrong with me. Is there even anything wrong with me? Are these things normal?
How do I go about this? If you can give me advice or answers on any of these five things then that would be great.

I actually sleep a lot, probably more than I should. I'm a vegetarian though so could low iron or vitamins be causing this?