Crazy insulin resistance ????

So for the last 48ish hours, I have had INSANE insulin resistance for seemingly no reason. My blood sugar has been hovering over 200, and won't budge, no matter what I do. I've tried changing my site, changing my insulin and exercising to no avail. My sensor says it is 280 and raising right now, even though I have active insulin in and set a temp basal at the max of 2 units of insulin an hour. I have no idea what to do and no idea why this is happening. I haven't eaten anything weird (I don't eat gluten/ many carbs anyways) and I'm not sick (that I'm aware of). I checked my ketones and they showed up as 'trace' so I'm not worried about that. Has this happened to anyone else??? What worked for you? I'm worried and have no idea what to do