Answer that yourself.

If you can't think of a reason to resub, then it's time to take a break. Go play other games. Pick up a pair of knitting needles (it's surprisingly therapeutic). Find a good book. Chat with strangers at Starbucks. Look up and marvel at the wonders of the universe in an open field at midnight. Call your folks if you can (they probably miss you).

If you keep playing when you can't think of a good reason to do so on your own, you're just going to burn yourself out, and will waste time and money doing something you don't enjoy. Take a break, and if you can remember things you miss, come back online and visit Eorzea again. I can guarantee it's going to be around for a long, long time, and will be here if you ever want to return.