Everyone's experience is different. I started getting DPD when I was 16, too.
I'm glad you still go on about your day and get things, and engage in activities! Keep that up
I feel like a lot of people who get DPDRD start developing obsessive thoughts which may be is one huge factor in feeling worse.
I would recommend reading about dealing with OCD, not saying bc you have it, but because generally people with anxiety can benefit a lot from learning how to deal with obsessive thoughts. Trust me on this.
I hate the disorienting feeling, too. I get the unexplained lightheadedness and nausea, too.
My advice would be, don't try to fight it, live with it. Take a step back mentally for a second, acknowledge how you feel, how your brain feels. After that, accept it; as in don't react much to it as much as possible. It may sound hard esp at the beginning but it's doable. Then, go on about your day. Let it accompany you when it insists. There's nothing you can do to change the way you feel, you are.
That, and learning from online resources how to deal with obsessive thoughts, especially helpful with getting panicked when you remember "it" again (I used to be that way so I know), a lot lies in the way your brain reacts at moments like that, and figuring that out eventually can help tremendously.
And compassion for yourself. You've got it.