Any time anything unfortunate happens, you have to just do as Mini suggests, move forward, but remember how you felt after you had "cheated" and remember it well - it will serve you for when you feel like cheating again.
Whats done is done, so draw a line under it, and remember that you can start again from now,
right this second! and not wait until tomorrow (I lose count of the number of times I've heard my Mum say at 6pm "oh I've had a biscuit now, oh well, I'll start being good again tomorrow....")
A blip is a blip, but it's only a blip, and doesn't have to ruin an entire day
Best of luck for tomorrow!
PS: Ketosis after 2 days isn't uncommon, I reckon I was pretty much right in it by mid-day 3, as Mini says if your OH has been cutting down carbs then that'll have made it quicker too, though everyone is different. You'll be there too, soon enough