I feel my negative thoughts slowly melting away.

Frost does not leave a windscreen evenly. It goes in patches. A clear arc where the blower reaches, a stubborn wedge in the corner that lasts another five minutes while you sit there with your hands in your sleeves.

Nothing about that means the heater is failing. It means the process has a shape, and the shape is uneven.

Expect the same of a bad stretch. Some days will be noticeably lighter, and then Thursday will not be, and Thursday is not a reversal. Slowly is the honest speed for this, and slowly still arrives.