Hi Madi, welcome to TeenHelp!
I agree entirely with Recommencer - although it might be really scary, it's better to get the cavities taken care of now rather than waiting. It's very possible that the longer you wait, the scarier and more invasive the procedure might be. I know that sucks to think about and puts you in a really awful position, given how traumatic your experience was, but getting it out of the way quickly seems like your best option.
However, it's very possible that your next experience will be different! I'm surprised that the dentist didn't really communicate anything to you about what was going on (that seems unkind and unprofessional of them), but if you ask them to, they may be accommodating. I also strongly recommend that you tell them if anything hurts, because you definitely are supposed to be completely numb during a filling. It might help to have one of your parents, or really any other adult, in the room with you - even if all they do is sit there, the dentist might feel more accountable and pay more attention to whether they are causing you pain if they know they are being "watched." But if you are hurting at any point, definitely speak up! Raise your hand, make some kind of noise, etc. It would be incredibly unprofessional and unethical of them to ignore you.
Dealing with anxiety in this kind of situation is tough. If you can change dentists, even within the same practice (which wouldn't require switching offices or insurance or anything), I definitely would. Some dentists are awful, but some are really kind and will walk you through everything and will make sure they're not hurting you. You can probably google dentists' names to read some reviews that other patients have left to help you choose one. But if you can't change dentists, there may be a few things you could try to help you stay calm, like listening to music/podcasts/an audiobook through headphones during the procedure. Dentists will usually allow this! Some also have the option to let you watch a movie while they're working. If those are both a no-go, you could also just try to daydream a bit to distract yourself or go through some grounding techniques, like the 54321 method, progressive relaxation, etc. Maybe also consider letting your parents and the dentist know that sometimes you have panic attacks, and if X happens (e.g., you're shaking), it's because of anxiety, not because of the numbing agent, and you might need them to take a break or check in with you to make sure you're doing okay.
Hopefully this helps. I'm really sorry that you had such a traumatic experience, and I hope that the next time is better! Best of luck to you, and please take care of yourself.