Our type 1 behaviors can change at any point in time. And they can change back the same way. I'm not sure how long you've been a type 1, but at the beginning we go through a honeymoon period where we still make insulin for a while until we completely stop, and that can take years for that process to happen. That means your insulin requirements will steadily increase.
But other things can change your normal pattern too, monthly hormone changes really throw some people off for a week every month. But there are lots of other things too. Infections, sleep patterns etc.
Humilin is not one of the most favored basal insulins nowadays. Generally it's twice a day for a more steady dose. It's cheaper if that's an issue, but some of the newer insulins are a lot more steady in how they work. Tresiba seems to be one of the preferred ones. I used to use Lantus. They seem to be a little more steady in how they work, but some people even split those into 2 doses when they have issues.