Same. My breakthrough infection lasted over a week. Nothing serious, but definitely very infectious, so I self quarantined. I’ve had minimal social contact and just about avoided COVID the original, so it was surprising how quickly I caught Delta after it became dominant.
Since more people are vaccinated, they don’t always know that they carry. It adds a lot to the contagiousness. They may also be less careful, due to the insurance paradox (insured people have more accidents).