Why the difference between am and pm?

I am a Type 2 diabetic on insulin. I am on Humalog 50-50 insulin pen.  I take 35 units plus a sliding scale in the morning. My glucose is about 158. At lunch time when I test, I am around 99 or so. I get 8 units of insulin and then eat lunch. At 6:00 p.m, my blood sugar tested 267 and I had not eaten anything between lunch and dinner. This is not unusual, I have been running in the 200's at dinnertime. I am nervous and depressed to have such a high level. I take 45 units of insulin at dinnertime plus a sliding scale. I also test at bedtime 11:00 p.m. and take as many units as the sliding scale calls for. What could be causing this? I have Fibromyalgia and do have a little pain in spite of the Lyrica I am taking. I do not feel very well at dinnertime and I am quite upset about having such a high reading without eating anything. Thank you for any help or advice you may have.

[Tink70]

You need to have a snack between lunch and dinner.  Light one.  Balance the carb with protein.  Cheese and crackers.  Something like 2 slices of cheese and 5 Ritz Crackers.  You probably aren't eating enough carbs to balance out the 8 units at lunch on top of the 99 reading you already have!  Your liver will make sugar if it thinks your body is in danger of going too low and its like a weird boomerang effect.  You have to keep your levels steady.  What time is lunch for you?  If it is around 5 hour time gap - test at the 2 hour mark after you eat and see what it is...then test it at the 3 hour mark.  If you are around 130 to 120 - have a SMALL balanced snack (cheese/crackers or something of that nature)  then test before dinner and see if it makes the difference.  I have this problem too.
Hope it helps.