Illness Around Infusion

Does anyone else get particularly sick right before and right after their infusion? I’m on Tysabri infusions on a 4-week cycle, and I’ve increasingly started feeling really ill for a day or two prior the infusion itself, and then a day or two following. I’ve been taking this for nearly a full year, and it wasn’t this bad early on. It feels like COVID or the flu levels of fatigue and brain fog, but not much else, and I’m testing negative for actual sickness. I know about the crap gap, but I’m trying to get a better sense about if this is normal or if I should start looking into a different infusion, though Tysabri’s kept my condition stable so far.