Here's the thing.
We're pretty laid back as far as moderation goes. We get accused of being too lenient more often than being too strict in general. Registering multiple accounts is against the forum rules and for good reason - someone comes in, makes a complete mess of things and then gets banned. Comes back under a different name, repeats behaviour, banned. Pain in the neck and disrupts otherwise good discussions and / or discourages people from posting.
However, we're also a forum of over 20 years existence. People grow up in that time and some mature. They're not the same person they were 15 years ago and have made life changes or just gained perspective. They come back and you don't even know that they're the same person.
Others need to just step away and leave things be.
No, I can't change your username to "MriyaMachine" for good reason. That account exists. You created it.
I don't know if your amnesia is medical or substance related but in either case I'm sorry but you need help, and not from here. As others have pointed out this isn't your first, second, third or even fourth account.
My recommendation is to stop posting in this account. Contact me by PM if you're struggling. Otherwise your username will be in red.