I used to read all the potential side-effects too and stress about them. I have only recently been diagnosed with generalised anxiety disorder (so I understand the anxiety, bigtime!) and OCD, so once I get an idea stuck in my head it's hard to get it out.
The thing is though that the risks for cancer in the general population is so high anyway, 1 in 3 for women I think, that you have to weigh up the relative risks. You know you have MS, but you don't have cancer. MS is actually associated with a lower risk for certain cancers, and a very very few a higher risk.
Maybe I'm just being too logical about it but I think if you are experiencing symptoms of MS right now, you should deal with things that are happening now. I have often found it takes up to 6 months for Copaxone to kick in properly as I've been on and off it due to pregnancies in the past. Do you have a nurse in the neuro's office you could talk your concerns through with at all?
The other thing that jumps out at me is advice I should have taken myself a decade ago
- only now am I tackling my anxiety and the relief that a good medication can bring. I also have had bladder issues for 2 decades, although in my case it is the opposite of retention, but if you haven't been to a urologist or for a bladder scan/urodynamics testing, it can be very helpful and you may find it it easily solved, it would give you great relief.
Wishing you all the best with your decision, PM me if you want to ask anything, and let us know how you get on if you can,