I left DD once for 24 hours when she was 10 months and still co-sleeping and nursing (I was a SAHM with her at the time). Prior, she was accustomed to taking the occasional bottle of EBM from DH, but not during the night. But she did take the bottle at night, slept with just DH, and otherwise did fine while I was away (was I maybe a little insulted? Yes!
). But, thinking back, I am fairly certain I knew she would be fine beforehand, just judging by her personality. I actually didn't feel a lot of apprehension when the time came to make the decision, and then to go (not that it wasn't hard to say bye bye, or that I didn't miss her!). But it was just...ok. So, if you find yourself REALLY uncertain, I would definitely listen to that inner voice too...obviously all LOs are so different.
On a practical note, I pumped over 30 oz in maybe 5 sessions over that time? So do plan on scheduling that (maybe bringing a hand pump to pump on the fly) and storing up that milk if possible (unless you're REALLY celebrating a lot