Right, start again when you're feeling up to it and and resolve to go two weeks with no slips at all, no matter what. No choccies or anything but what's on the legal induction list and the occasional sf jelly or mim. Have a little break now if you need it but when you start up again, make a deal with yourself, 2 weeks no slips -at all-, and hide the scales for those two weeks. I really think you'll see a loss if you manage to do that, and if not we'll know something more needs to be done.
ETA: you might want to have a look as slimming world red days. It's their version of a carb lowering, low GI diet, but not ketogenic which means you can have the odd treat like a chocolate within your points allowance. You do have to eat low fat foods but can still eat well, and it seems to be the plan people have the best losses on. Maybe it would work better for you right now? Ketogenic diets require as hardcore adherence to the rules as things like Cambridge, really, and it can be very hard.