I did think Toujeo probably wasn't the best choice of basal but it is one of the cheaper insulins. The advice about starting on a couple of units when fasting levels start becoming consistently above range is quite sensible and using a small dose of NovoRapid with meals, but you will need to find a balance with the carbs in those meals and the insulin they need. It is common for Drs to recommend 1u:10g carbs as a starting point, but some people are more sensitive to insulin and may need a much weaker ratio 1:15 or 1:20. So start with less and err on the side of caution and then you can always increase it if/when you need to. It is important to know that NovoRapid has an activity time of 4-5 hours. Most of it's activity is in the first couple of hours after injecting and if you exercise during that time, it will increase it's effectiveness, so generally we reduce our meal time insulin dose if we intend to exercise afterwards, or we top up with carbs whilst we are exercising.
What is your low alarm on the Libre set at? The factory setting is usually 3.9 but I would suggest you set it higher. I set mine at 4.5 but 5.0 might be better for you since you have had such an awful experience with hypos. I am not suggesting you take a full hypo treatment when the low alarm goes off, but maybe just a small portion. It is important to understand that we are all different but with mine set at 4.5 if I am dropping very fast when the alarm goes off ie a vertical downward arrow, then I have 2 jelly babies and that will usually turn the drop around and level me out at about 6 in half an hour. If it is just a sloping downward arrow between 4.2 and 4.5 then a single jelly baby (5g carbs) is enough. If I get an horizontal arrow when the alarm goes off I generally just keep a close eye on things. If I know I have food in my system which is going to digest and bring me back up, then I won't have anything, if I know that I am going to be exercising or I am exercising I will have a jelly baby and see how that goes. I find it amazing how powerful 1 jelly baby can be in raising my levels and I have to be very disciplined with them otherwise I will end up high and need more insulin to bring me down and risk another potential hypo. I see my jelly babies and insulin a bit like the accelerator and brake on a car. If I am going too fast I need to slow down but that doesn't mean I need to do an emergency stop, just gently slow down, but if I am going really fast then I need to be a bit firmer on the brake. Ideally I learn to mostly get my speed right without needing too much brake (jelly babies) but it comes with experience and you can't get good at driving without practicing. Not sure if that makes sense to you but it is about balancing your insulin for the food you eat and the exercise you do plus the other 40 factors which impact BG levels like alcohol and hormones and ambient temperature and how well you slept and illness and season and time of the day even as we tend to usually be less sensitive to insulin the morning compared to the evening.
The timing of when you inject your NovoRapid is also important because we are injecting into subcutaneous fat and it has to get from there into the blood stream whereas the pancreas releases it straight into the blood stream. This means that we usually have to inject it a little bit in advance of when we eat. This is called prebolusing. The patient information leaflet probably suggests something like injecting 10 or 15 mins before you eat but often we need more than that before breakfast than we do in the evening. If you don't inject far enough in advance, your levels will spike high because the glucose gets into the blood stream before the insulin and then it may be that your own pancreas will kick in and release some as well as the insulin you have injected, because your pancreas responds to the elevated BG levels, so you might have injected the right amount but too late and then your pancreas adds in some extra which is then too much. If you wait too long after injecting before you eat, you can end up hypo as the insulin arrives in the blood stream before the glucose from your food. I used to need more than an hour at breakfast time between injecting and eating breakfast but at other times of the day, I just needed 20-30mins. You have to carefully experiment to find the timing which is right for you at different times of day. I wonder if it might be helpful to start your insulin with just one meal, perhaps breakfast and have the same breakfast every morning and work on getting the dose and timing right, since your own insulin production seems to be managing reasonably well at the moment, so there is no huge pressure to use insulin for all 3 at the moment.
I appreciate that I am giving you a huge amount of info all at once and it may seem very complicated, but just like learning how to drive, it gradually becomes second nature and you do most of it on autopilot, like looking in the mirror and indicating and changing gear and wiping the windscreen etc. When you first learned to drive you had to think about every single process, but gradually your body/brain just develop a muscle memory for most of those things and just do them automatically in the background. Break it down into small sections like one meal at a time, experiment carefully and always err on the side of caution ie less insulin rather than more, and find what works for your body for that meal at that time of day. When you have a routine that is working reasonable well, start with another little step, gradually building up your repertoire of meal doses and timings and most importantly your confidence.
