The same thing happened to me 2 years ago... I broke at least 10 spokes on the rear wheel in 7000 miles.
I heard it was most likely not enough spoke tension, even though they seemed plenty tight to me (by feel).
So, I got a Park tension meter, and found that my tension was too low, but I was sure if that was the true cause.
I was surprised how tight a proper spoke feels by though.

Later, I got a new 32 spoke wheel, the spokes were at the right tension when new, but after just a couple of weeks some some got too loose.
So, I started checking every 6 to 10 weeks (1000 to 1500 miles).
In the last two years, maybe I broke one spoke. Perhaps it was tension, but I'm not planning to check the tension every 2 weeks.

Of course, 36 spokes would be better, but it could be your spoke tension.