Mixed insulin, like yours, works great if you eat the same things at the same time each day.
Not so good if you chage meals times, or meals.
It really is worth considering changing your reigime for a bolus/basal one.
Thw twice daily one works by giving you x amount of short term insulin, and x amount of longer term insulin. The short term covers your meal, and the long term covers when you aren't eating.
You're eating too many carbs for your insulin to deal with, so you give yourself more insulin. But, this insulin keeps on working all the time, long after your meal has been digested, which is why your levels are going so erratic.
Your levels are generally wuite high it looks like, and personally I think that bolus/basal would be worth looking at, it gives you more flexibility and although you have to have more injections, i think it gives a lot better control.