Obvuous options
Check for availability on QR from USA-DOH since it may well check the bags through
Change award ticket to include both flights if there is availability
Change the flight from DOH to the next day and just have a day in Doha - no need to worry
check the penalties on the flight from DOH and determine what the cost would be should the AA flight be delayed - make sure to make changes before you leave the USA since QR often has high no-show penalties ; just simply accept the risk
cancel existing award booking and purchase a ticket on QR
travel withour checked baggage

Personally , with 2 separate tickets, I would change the onward flight to the next day , have a (close to) risk free journey and enjoy a day in Qatar