It sounds like you're working hard to learn the stuff that you didn't do well on before.

As far as what other people said about maybe rethinking your grad school plans if you have problems with math, only you know if you have an aptitude problem with higher math or if the low grades are because of not keeping up in class and doing problem sets and studying regularly.

I've been in that spot before, where I had to make a good grade on the final to pass the class. It's a huge amount of stress, but it can be done. Best of luck to you!