I love the sport, but I am horrible at basketball.
I've never played, but we used to play a similar sport played on a rectangular court. It's known as netball in the UK, where I'm originally from.
I have never heard of that.  Can you tell me more about netball?
It's the same principle in that each team tries to pass the ball down the court and shoot it through the net, just like in basketball.
Are there professional netball leagues similar to basketball leagues?
There are, but not as well established as basketball. There is a governing body, the INF, which administers the rules - they standardized them many years ago.