Sue, I don't think you are hopeless!!!
Maybe you are just not in the right frame of mind?
Think perhaps you have got so many things going on in your life at the moment, it may just not be at the top of your priorities.
May just be worth taking a few minutes out before you go shopping to plan the meals for the week ahead. That tends to work for me, I've also got the meal plan for the week on the fridge, so that I can check the night before to see if I need to get anything out of the freezer for the next day....mind you this is still not idiot proof,yesterday I had the meat ready in the slow cooker & forgot to turn it on before I went to work....suddenly remembered at 4pm oops, quick change of plan!! x