I was on Rebif for about 4 years and hated it. I hated the expense (though I do have insurance), I hated the needles, I hated being attached to the fridge (so to speak), and in the end, I could simply not justify paying (or having the insurance pay) huge amounts of money (from my perspective) for something that had so little benefit. So eight months ago I stopped. I didn’t taper off, I didn’t discuss it with anyone, but simply did not give myself a scheduled injection. In my case, this did not have any ill effects, if anything, I feel better and my hair has stopped falling out at the alarming rate at which it did fall out while I was on Rebif (I was the only one concerned about this). I have regained my emotional equilibrium (Rebif did do a bit of a number of this). Mind you, my experience with Rebif was very different from yours. I did not have attacks while on it (or since) and did not have extreme physical reactions to it. Keep in mind that everyone reacts differently and you may want to talk this decision over with your GP or your neurologist or your MS nurse (if there is an MS clinic in your area), with someone at any rate who has followed your case.
Hope this helps and good wishes