Existential dread is a real thing. It sets in over the course of months and years, making you feel like you've missed out or you're missing out right now. You shudder to think about the implications of it all. The dread is caused by the lack of a meaningful purpose and the meaning is defined as having a definite goal.
The real cause of dread is that the human mind can't think beyond "here and now". This is mainly due to us being programmed to struggle to survive and improve our standing right here and now. If you can't find a measurable goal, you can indeed feel like floating in the nothingness of space, disoriented and completely still, even though you're moving. Therefore, the main solution to the dread is to think and strive towards the ultimate goal.
No matter what it is you're trying to do, it will probably take you decades. Nobody can really teach you to plan that far ahead but that's exactly what you have to focus on to keep the dread at bay. In essence, you need to articulate actual steps that will move you to your goal. For example, if you're under mom's and dad's patria potestas and want to become emancipated, you shouldn't be thinking "my goal is emancipation" but rather "my ultimate goal is emancipation, which I will reach by learning myself how to cook, clean, maintain hygiene, good mood" and so on.
What the dread shows is that you lack discipline and are giving yourself too much time to think. You should be constantly engaged in learning new things, seeing and hearing new impressions so you can become the kind of person you want to be. If you're feeling dread, you've fallen out of the groove and are drifting away.