Interesting to hear about your journey, thanks. I did about the same four weeks back, for 2 weeks, mostly to see what it felt like. One thing I did was to order some keto sticks off Amazon - five quid, next day delivery - to know when I got into ketosis, and it turned out that was on day 3, but we dieted pretty hard the first 2 days.

Neither my wife nor I "felt very different", apart from being a lot less able or willing to do intense, sustained work (e.g. run fast), but I sure as hell lost stomach fat quickly.