I have a few thoughts:
1. Have you tested for ketones?
2. If you are like me and a lot of other type 1's, your correction factor is not static. By that I mean if you give 1 additional unit for every 25 mg/dl BG that you are over target, that isn't enough. You may need to add an additional 5%-10% for highs. Example: If your correction factor is 1:25 (insulin:BG), target is 100 and BG is 300, then you would calculate 8 additional units of humalog. Except for me, that won't be enough. I'll add another 5%-10%. Of course, with a syringe, it isn't as easy to measure precisely, so I would try to measure 8.5, or halfway between 8 and 9 if the syringe does not have 1/2 unit markings.
3. Have you done any basal testing lately? Some diabetics have this idea that basal testing is only for pumpers, but I would wholeheartedly disagree. The way the data is used may be different, but that doesn't make it any less important. If you haven't done basal testing, you don't want to do it if you are running high for obvious reasons, so don't do that just yet.
4. Have you had unusually high levels of stress or any other factors that would raise your blood sugars? You are sure you are over the flu, right?
5. Are you developing insulin resistance or could it be getting worse? I have the opposite issue. I have both type 1 and type 2. Like a lot of others with type 2, my resistance has decreased as I've lost weight. At one time, I was taking 150-200 units daily. Now my average is less than 70 units daily. I realize that type 1 will never go away (unless someone finds a cure... it should be 10 years from now, or that's what they have been saying for 50 years now), but type 2 is a different disease (a metabolic disease vs. type 1, an autoimmune disease) and losing weight helps most type 2's.

Be sure the Lantus and Humalog you're using are okay. When it's a strange change, and not explainable by illness or excess fat or high protein in the diet, it could also be a bum bottle of insulin. It's rare, but worth considering moving to a fresh bottle.

I have had the same issue this month, after opening a new vial of Apidra. I need to refigure my ratios every time I open a new vial, so frustrating! This is a more baffling week as sometimes the injections work to lower the high BG, and other times not. Could it be the injection site I am using in my stomach? I took 6 units after lunch today and 3 hours later my BG was 400. It was like I didn't take any insulin at all. I am not sick at the moment, so I don't have Pattie's problem. Anyone with insight, please respond?