Hi Liana--Yeah, some days are just like that.
I've found that when things get off, some days will right themselves and others, we just make it through until bedtime. What I've always tried to do is stick to the Es, and build A times/naps around those as needed.
I think you did the right thing in just feeding him and letting him go down for his nap. Once he has a full nap under his belt, he'll be able to do a full A time again. Let's say that your LO sleeps for 1.5h. That means that his day probably looked like this:
Awake at 7
E: 7
A: normally ~1h20 (right?)
S: normally ~8:20
But, he did this:
A: until 9:30
E: 9:30
S: 10
Something like that. So, he'd sleep until about 11:30/12. Just feed him at 12:30 (or 3 hours from when he last ate), and do have him asleep 1h20 after he woke.
Because every situation could be different, it's hard to say exactly how to get the day back on track. But, by sticking to E times, trying to get full naps in, and making sure that you're doing what you can to avoid more OT/OS, then that's what's best. Don't be discouraged if you just have an off day. Just start afresh tomorrow!