I don't know why am I apprehensive when a Remicade infusion is due

I'll take a third infusion in the morning but every time I have remi I'm worried. I don't know why. I've undergone 2 surgeries, several upper and lower scopes, a number of CT enterocolonographies which I loathe and many MRIs and I never felt like that. Even when I used to take a weekly Methotrexate injection and what it used to bring about from vomiting and nausea, I was never worried. I can't find the reason why I have insomnia on the eve of the infusion. Does it happen to anybody?