Passing Mathematics Courses

I'd say overthinking. Is there any specific part in Trigonometry that you find challenging?

PS: When I look at my old engineering math books now, all the 'impossible to understand' topics look super easy.

Trigonometry is a bit ‘tricky’nometry.
In 1956, our text book was the then gold standard ‘Plane Trignometry’ by S.L.Loney. I found it very good. It is available for free download from archives here. Worth looking at.
<a href="https://archive.org/details/planetrigonomet00lonegoog" target="_blank" rel="nofollow noopener noreferrer">Plane trigonometry : Loney, S. L. (Sidney Luxton), 1860-1939 : Free Download, Borrow, and Streaming : Internet Archive</a>

This book below will get you off the discouragement. The author hated maths. She became a professor of Maths later.
A Mind for Numbers: ‘How to Excel at Math and Science (Even If You Flunked Algebra)’ by Barbara Oakley.

I got it for my grand daughter, who has a similar dislike of maths. It is a great book. We play at maths. I pretend to be a duck,who is great at maths, and squawk about how good I was. Then I make silly mistakes. Tara (my granddaughter) will whack me on the head saying ‘grampa, you know nothing. This is how it is’. (I am only 68 years older than her.) But she remembers what it was that we were discussing in algebra that was troubling her.

Thumbs up for S.L. Loney! 😀

Thank you both for the encouragement. I am mainly struggling with proofs in my class. I will definitely look into your suggestions!