Hi Rach,
It’s great that you’ve started.
Don’t worry, you’re not going to mess it up. Like you, when I first started I kept finding I had so many ingredients left over I ended up having to repeat Week One meals a few times. In the end I gave up on the weekly menus and made my own meals, only adding in a recipe from the BSD book every now and again. There are a lot of people on here who have never used the recipes. As Birdy says, as long as you keep to the 800 cals and keep your carbs low-ish, you can switch meals around, or use your own recipes. It still works.
One of the food trackers (e.g. fatsecret or myfitness pal) will help you keep track of your daily cals and carbs, and help you plan your own daily/weekly meals if you want. Also, quite a few people go for 2 meals a day – lunch and dinner – so you’re only having to split your 800 cals by 2 not 3.
MM doesn’t really go into how many carbs you should have, but reducing them really helps with both the weight-loss, putting diabetes into remission, and other health issues e.g. PCOS, non-alcoholic fatty liver disease, reducing blood pressure, etc. I’ve never had PCOS but it helped me sort out all of the others.
Remember to drink plenty of water.
Best wishes
Jennie xx