Hi Brenda . I've had 5 infusions and have been getting what I call a 'Ty hangover' the day after my infusion. This started after my third. I feel about the same way you described except it doesn't start until the day after and lasts that whole day. I feel like I did when I was on Avonex but it only lasts for one day. I'm going to talk to my neuro about it when I see him at the end of the month. I'm so sorry you're dealing with this too