15 Month old fell down stairs
I agree with everyone else that it can't hurt to take her to the regular Dr., it will make you feel so much better. My son (2.5) has vomited just from crying really hard several times. Seriously, though, don't beat yourself up over it, or your husband over it. People make mistakes, and kids fall down plenty no matter what you do. Sounds like she's acting fine now, so she's probably just fine.
Falls happen. My father fell down a set of stairs as a toddler, well actually he jumped thinking one of his sisters would catch him, but that wasn't the case and he had the misfortune of going face first. He did mess up his teeth but no lasting isssues. My nurse friend had her 10mo roll of the changing table when her H walked away leaving the 4yo in charge of watching her , she's almost 3 now and has no issues. Like others mentioned, vomiting is a sign of concussion, but concussions can happen without (I've had both), but after 48 hrs and no other symptoms, you're pretty much in the clear.