Monthly meal-plan and shopping

Do you have any tips for me?

I try and do 'cook once eat twice' and meal planning, but still find I'm spending more than I'd like and end up going to the supermarket for lunch. I often find myself falling off the wagon at the end of the week and just having soup/chips/baked potatoes.

I enjoy cooking but don't want to spend the whole weekend doing it as I'm busy with other things. I own a breadmaker, and do use it regularly.

I'm also vegetarian and don't eat pasta more than once a week, as it makes me seriously put on weight. I can't eat cheese or chocolate often due to it giving me bad skin. I also hate sandwiches, just feel too stuffed from the bread.