Was I At Fault For A Car Accident If I Was Completely Stopped When The Other Truck Hit Me?

Location: California

I was recently involved in a car accident in California and I’m trying to understand who may be at fault and what I should do next.

I was turning left across two lanes of oncoming traffic into a gas station. A truck in the lane closest to me stopped and waved me through, so I started to go. I did not initially notice another truck approaching in the farther lane.
As soon as I saw the second truck, I stopped completely. My car was still in Drive and my foot was firmly on the brake. Everything happened very quickly, so I didn’t have enough time or space to speed up and get out of the way or back up. At the same time, I had enough time to see the truck getting closer and believed he was going to stop because I was already completely stopped. However, he continued toward me and hit my passenger-side door.

My airbags deployed, the passenger window broke, and my car is totaled. The truck that hit me reportedly has a small dent and scrape where it hit me.

The police came to the scene. No one reported injuries at the scene, and I wasn’t given a ticket or paperwork. The officer said we were good to go and that insurance would handle it. I had provided old insurance information because I currently do not have active auto insurance.

I am going to go to the hospital and get checked, as I think I may have a concussion, but I also want to understand what will happen legally and financially.

Can anyone offer any insight or advice? Am I automatically considered at fault because I was turning left, even though I came to a complete stop before the truck hit me? Does the fact that I was already stopped when he hit my passenger side change anything?

Also, what happens if I don’t have insurance?
I’m not trying to avoid responsibility - I genuinely want to understand what my rights and responsibilities are and what I should do next.