It is easier to realize that software development was never engineering. Physical engineering is reliant on physics, while software is reliant on other software. Physics are static and as regarding practical engineering is known and can be applied rigorously and taught in courses. Software is constantly changing, contain tons of edge cases, and as we can see by recent developments, can change in unpredictable ways and lead to entirely new paradigms.

So, the software that you learned on is changing. You aren't going crazy, but the ground is indeed shifting. The problem is that you assumed it couldn't shift because you were applying the wrong constraints.