How do I ask for help to find out if I really have this?

Okay so I honestly think I have Depersonalization disorder. I feel as if I have all the symtoms and even took a questionarre on a .org site about this and it said i have it severely. I even remember being with my boyfriend one time and I couldn't even enjoy my time with him because I just kept looking around and nothing felt real, it felt like i was in a dream and could not wake up. as if whatever i did in that moment would not exist in the real world when i came back, wherever and whenever that is. that was definitely the most severe and significant experience. i can honestly say it scared me ALOT. I was completely sober aswell, in case that was a question. i'm not gonna sit here and list a bunch of experiences i've had though, because point it i have feelings like that just about every day, maybe not as severe all the time, but i don't know what to do about it. i'm 16 years old, i don't feel like i can tell anyone. i feel like my boyfriend may act supportive but secretly will think i'm just over-reacting or going through a phase. my mom is what i'm most worried about though, because she will be the worst. i know she won't take me seriously and will just think i'm going through a phase as well and just think i have it because of what i read online. she might even think it's just because of pms, or come up with some sort of excuse.

overall, this stresses me out alot and whenever i'm around friends or even in class trying to do work i can't even concentrate on what i'm doing alot because i feel like i can;t control myself because i don't feel like i'm in real life. meanwhile i feel like every one is just fine. i constantly look at the world like it's some made up fantasy and one day we'll all wake up and never exist(WOW it feels good to finally let this all out) i often don't feel like reality exists. i can't talk to any of my friends about this because nobody will take me seriously. i'm scared of what will happen if people find out, yet i want this to stop.

please, any help or suggestions on getting my mom to take me seriously or how to get help, or if you think i even really have this?

In the Dissociative Identity Disorder forum here, there are a bunch of "check in" threads about self assessments, and some other resources. You might look around there and see if the phenomena described by others seem to match your own experiences.