Brabio reaction

Hi, I was diagnosed in 2005. I’ve had tysabri, fingolimod etc etc. I am now in secondary progressive stage-cant walk anymore. I have been doing brabio injections 3 times per week for past 2 1/2 years. In the last 6 months I have had a reaction 3/4 times to the injection. As soon as I’ve done it I feel as if I will faint & have an intense shooting pain across my lower back. It takes about 10/15 minutes to pass & afterwards I feel shaky & weak. It has happened with different injection sites. I wondered if anyone else had similar experience. MS nurse didn’t seem bothered by it, but doesn’t seem right to me. Makes me apprehensive when I do the injections. Interested to see if anyone has had same/ similar experience.