Make snapshots regularly of your instance, especially if it's a Spot Request.
I would "SSH-in" and do a check of what's currently running, just for my own information. It wouldn't hurt to stop anything that doesn't neet to be running...
reg$ ssh ubuntu@54.147.55.37 "ps axjf"
Creating a new AMI image based on the current instance.
This will also create a snapshot of the instance's boot volume.