Reece I think it's part of the adjustment to living with MS, long-term. I used to visualise my MS in a lovely green handbag, with me, walking up to a bus stop and leaving the bag there! But real life means you carry that bag around all the time.
I feel there is a very very fine line between adjustment and depression, and perhaps you'd gain some relief from the more negative thoughts that are overwhelming you if you explored the idea of anti-depressents with your neuro/gp.
I suspect living with a high level of fear or dread would not positively impact on your MS, and it certainly is exhausting - been there, done that, especially in the first 2 years after diagnosis (I'm now nearly 11 years after diagnosis and the panic does die down).
I am taking a very low dose of antidepressants for nerve pain, and they also help my overactive bladder at night. But a lovely side effect has been a slight reduction in the negative worries that sometimes got the better of me. I'm not saying I don't worry, and there are days I unfortunately spend the best part with a sense of fear in the background when my MS is revving up, but I have to be honest and admit the AD's are helping more than my nerve pain.
I used to be very rigid about not taking AD's - I didn't want anything changing my personality. But I realise now that fear, and unrelenting nerve pain was changing my personality and that by treating both of those I've brought myself back to some kind of normality again.
Best of luck
RR-MS dx 1998 and Coeliac dx 2003
Copaxone, Cymbalta. EPO, Fish Oils, Vitamin D3 2000 IU daily, Cal/Mag/Zinc, Multivitamin/mineral, Co-Enzyme Q10, Probiotics, Milk Thistle.