You *can* do subjects like Economics or Finance at university without Additional Maths at SPM - depending on which school, not all will allow it - but you have to think of each step (for you the next step is Pre-U). Basically if you have Maths at Pre-U then not having Add Maths doesn't matter quite as much. But you will then have to work very hard during Pre-U (this is not as hard, as there certainly will be a lot of new things anyway - catching up Maths in uni or Further Maths in A Level is probably way harder).

You can even major in Finance without Maths... as long as you stay away from Financial Mathematics, Quantitative Finance, Computational Finance, Computational Economics, Mathematical Finance, Mathematical Economics, Econometrics...