I've had Type 1 for just over 20 years. Over the past six months I've had to start taking a lot more insulin. Like you, about double what I was taking before. I've tried switching back to Humalog (I use Apidra) but it has no impact, so I think it's insulin resistance.
I am, however, overweight (although my weight hasn't changed in years), and so I'm hoping my insulin needs will decrease as I lose weight. My weight has been holding steady, I haven't found taking more insulin caused me to gain weight.