Why does Docker database keep getting removed every night?

I’ve got a 2GB Basic (22.04) Droplet running Docker for a my portfolio site (currently, will be hosting my other projects to display my previous projects). I’m new to Docker being ran for production, I’ve been using it mainly to run postgres, elasticsearch for development. Below is my docker-compose file for the current build I am having issues with.

version: "3.10"

services:
    backend:
        build:
            context: .
            dockerfile: Dockerfile
        restart: always
        volumes:
            - static_volume:/backend/static
            - media_volume:/backend/media
        ports:
            - "8000:8000"
        command: >
            sh -c "python manage.py collectstatic --noinput &&
            python manage.py migrate &&
            gunicorn project.wsgi:application --bind 0.0.0.0:8000"
        depends_on:
            - db

    db:
        image: postgres
        volumes:
            - postgresdata:/var/lib/postgresql/data:rw
        env_file:
            - ".env"
        ports:
            - "5432:5432"
        container_name: xxxx_db

    frontend:
        build:
            context: ./frontend
            dockerfile: Dockerfile
        volumes:
            - frontend_build:/frontend/build
    nginx:
        image: nginx:latest
        restart: always
        ports:
            - "81:8080"
        volumes:
            - ./nginx/nginx-setup.conf:/etc/nginx/conf.d/default.conf:ro
            - frontend_build:/var/www/frontend
            - static_volume:/var/www/backend/static
            - media_volume:/var/www/backend/media
        depends_on:
            - db
            - backend
            - frontend

volumes:
    frontend_build:
    static_volume:
    media_volume:
    postgresdata

It seems that every night the db is just being wiped, I’m able to re-run the migrations, docker compose down and up where the data will persist. But in the morning I get a bunch of errors from django implying that the database is no longer there.

I checked the xxxx_db logs and noticed this in the early hours of the morning:

2023-11-10 00:50:06.222 UTC [22891] FATAL:  expected SASL response, got message type 0
2023-11-10 01:09:59.536 UTC [23012] FATAL:  unsupported frontend protocol 0.0: server supports 3.0 to 3.0
2023-11-10 01:09:59.823 UTC [23013] FATAL:  unsupported frontend protocol 255.255: server supports 3.0 to 3.0
2023-11-10 01:10:00.117 UTC [23014] FATAL:  no PostgreSQL user name specified in startup packet
2023-11-10 01:35:07.437 UTC [23185] FATAL:  database "template0" is not currently accepting connections
2023-11-10 01:37:09.770 UTC [23252] ERROR:  cannot drop the currently open database
2023-11-10 01:37:09.770 UTC [23252] STATEMENT:  DROP DATABASE postgres;
2023-11-10 01:37:10.886 UTC [23253] ERROR:  cannot drop a template database
2023-11-10 01:37:10.886 UTC [23253] STATEMENT:  DROP DATABASE template1;
2023-11-10 01:37:12.020 UTC [23254] ERROR:  cannot drop a template database
2023-11-10 01:37:12.020 UTC [23254] STATEMENT:  DROP DATABASE template0;

Any help would be greatly appreciated as it’s driving me insane!

Thanks! Matt