Hey Santosaaron, welcome to AN

I did this subject last semester. Although I do consider myself a maths person (hence my major), I found that the textbook reading was very confusing, and I could barely follow it, and also mostly felt this way in lectures. TBH, for me nothing really sunk in until I actually tried the pretute questions, (and this usually took longer than it should have), and really took the time to review the lecture slides. Also, based on what my friends doing it this semester and last semester said, the general opinion was that it was hard to understand what was going on straight away, so definitely don't feel discouraged!

(I ended up with a H1 in the high 80s BTW)
As for your situation, I'd say you don't need to understand all the formula derivations. You just need to know what the formula is doing (e.g. For PV = c/r*(1-(1/1+r)^t), you should be thinking something like, this is the PV annuity formula, it's how much someone would need to invest today to get t payments of c at interest rate r in future ect). But if you're really really struggling, talk to stop 1, since unless it's a prerequisite (but I'm guessing you'll be avoiding FNCE subjects if you feel this way), you could surely delay it.
Best of luck, hope it all works out for you
