Short naps are completely normal at this stage, especially if he is going through a developmental leap. It's just good that he took a nap!
It's OK to feed a bit early and do an EAS AEAS routine if you need to...or even EAS ASE if another nap is due before the next feed. It's ok & usually necessary to be flexible with sleeps and eat times at this stage.
I strived and strived for a predictable routine with DS and nearly drove myself crazy with it and wasted a lot of his early months stressing about routines he wasn't ready for. With DD I expected unpredictability at first and was pleasantly surprised on the odd occasion she did something "textbook".
At this stage, try to keep A times and WD time in mind and you're providing the opportunities for naps, that's all you can do. The length of nap is a bit of trial and error and luck at this stage.