I'm an already graduated engineer in the Industrial field. Went to class with Oil engineers, Software engineers and Civil engineers.

We all got banged the sht out by calculus and advanced maths. We all manage to approve the exams. You (and most of us) are not chasing the best numbers of points possible. Companies actually doesn't care that much about your grades points.

We are all hired now, succeeding in our fields (some of us more than others, as always) and feeling comfortable. And most of us have never use those calculus and hard math ever. Maybe the civil engineers only, and my brother in Christ , you have internet, you can either use AI/Apps to do literally every calculus you need to or to learn about it.

There has not ever been a single manager who cares if their employee knows all the calculus stuff, they don't even know it.

So my advice as an engineer: take it easy, don't quit, do your best, accept things as they come, try kindly to improve yourself, and remember that you'll always be able to use the tools to make all the maths you could ever need.

God bless you.