Cavities are subjective. Conservative dentists will let small cavities and stains go, and just monitor them. Aggressive dentists will drill out everything, even small cavities that don't require anesthesia. Aggressive dentists make more money. Conservative dentists are often more ethical. However, sometimes its better to drill out a small cavity before it grows. Cavities are judgement calls. Just a large filling vs. a crown is also a judgement call.
I'd take the recommendations from the above posters, and not go to a chain dentist. Go to a private practice. I'd wait until its time for your next six month cleaning. The reason the hygienist barely cleaned your teeth is because time is money. She and the office get paid the same whether your teeth get fully cleaned, or simply rinsed. Sounds like yours only got rinsed. You could probably use a really good cleaning. Get a good, ethical dentist for your next 6 month appointment, preferrably one that is conservative. In the meantime, I wouldn't back to this dentist to get those cavities filled. You own those x-rays by law, so you can have this dental office send them to your next dental office at no cost.
Don't lose confidence in all of us, just some of us. Money rules the world.