American Airline Flight Cancellation Question

Why did it get cancelled? Weather you won't get anything. If it's a technical problem you may get a meal out of it. Doubt a hotel since it's not overnight

As stated you get nothing for weather. Mechanical problems or over booking is another matter.

It was a mechanical problem

I had a similar situation; AA cancelled my flight at 9pm after delaying it for 5 hours and couldn't guarantee me on any flights leaving the next day, so I rented a car and drove through the night. I sent an email HERE detailing how bad they fricked up, what it cost me, etc. They refunded me, obviously, but also sent a $300 travel voucher. It didn't make up for the fact that I had to drive 500 miles through the middle of the night, but it beats nothing.