Hi and welcome. I think checking blood glucose levels is essential if you want to control your condition, but it pays to do it in a structured way. Testing at set times doesn't tell you all that much - BG varies a lot throughout the day, bioth in response to food and because your liver is continually adding glucose to your system as and when it thinks you need it. Livers can get used to higher than ideal glucose levels being "the usual" and will attempt to keep them high.
I found that using the tests to establish the foods that have the biggest impact on your glucose levels pays off. Carbs will always raise glucose levels initially, but what you really need to know is how well and how quickly your body deals with them. That's why the recommended pattern is to test immediately before eating, to establish a baseline, and then two hours later. This is not testing to see how high you go - the high point will probably be around 45 minutes after eating.
Instead this way of testing shows you how well (or otherwise) your insulin response dealt with the carbs in what you ate. Carbs are digested to glucose and ideally your insulin should get you back at, or close to, the baseline reading within two hours. If not, there were too many carbs in what you ate for your system to handle at present, and that implies that the surplus glucose stays in your bloodstream at an elevated level for longer than it should.
So if (for example) you take a reading before breakfast, and then another two hours later, the +2hr level should be within 2 mmol/litre of the first (and under 8.0 mmol/litre). If it's outside that range, your insulin isn't coping with the carbs in the toast and the best course of action, if you want to reduce your BG level, is to reduce the quantity of carb in what you ate.
Does that make sense?
My guess is your sleepiness is caused by elevated BG levels falling - I used to get this.