Hi Jottie!
First of all, well done on adopting low carbohydrate as a way of eating; it really does help massively with blood sugar control when balanced correctly. It's definitely tricky to get that balance right at first though.
The standard way of thinking about hypos is that you haven't eaten enough. I tend to think, instead, that I've taken too much insulin. I don't agree with a lot of what the USA does, but they do have a much better name for hypos: insulin shock. Often, a high carbohydrate diet can mask big miscalculations in doses. I was on about 32 units of long-acting before I switch; now I'm on 14.
Higher doses can also take longer to get out of the system. I've heard of a study where someone without diabetes was injected with a large dose of insulin and provided with glucose via a drip until it was out of their system. It took a week for their blood sugars to return to normal. Sorry I can't remember more details (Dr Richard Bernstein referenced it somewhere). It could be that you've still got some legacy effect on your blood sugars from your previous higher carbohydrate diet.
I should probably also mention that a low carbohydrate diet can come with side effects in the early days of taking it up, especially if you substantially lower your carbohydrate intake rapidly. These often last for around three weeks, although everyone has different experiences. I found I needed to massively increase the amount of water I was drinking for a few weeks, and that I was tired for a lot of the time. I also got severe cramps in my legs; this was due to a drop in the amount of salt I was consuming. When I switched away from ready meals. my salt intake plummeted. We know we can have too much, but it's possible to have too little as well. I added a bit of bacon into my diet and sprinkled a small amount of salt on my omelettes and this cleared things up quickly. I also found that my sex drive dropped to almost nothing for a couple of weeks (although I've heard that others have had the opposite happen!). I've heard that a change in diet can also have a temporary effect on the timing of a woman's menstrual cycle, but as I'm male I can't verify this.
As previously mentioned, all of the symptoms I experienced were short lived. I've been following a low carbohydrate diet since January 2014, and it was definitely the right choice. Make sure you've got plenty of glucose on hand to ward off extra hypos in the short term, and try to make small and measurable adjustments where you can. Your ability to test with your Libre is also essential, but it sounds like you're already on top of that.
Best of luck with it all!
