did you mix it after you topped off? You may have been reading the water you added only. With extract, it's impossible to miss your SG unless you miss your volume.
BTW. Nice to see another FoCo brewer.
Primary: Exam Brown Ale
Primary: Unknown Mead
Secondary: Matt's Saison
Carbing: Raspberry Apple Cider 333
Enjoying: Lazy Ass Orange Pale Ale, Belgian Grand Cru, Belgian Dubble, Cherry Stout, Demonstration IPA
On Deck: Black IPA