I'm having an iron infusion next week but had no info at all, what does it involve, how long does it take also are there side affects?

Depends: Side effects and duration of infusion depend upon the pharmacologic type of iron being infused. Older pharmacologic types were associated with allergic infusion reactions that necessitated a longer infusion. Newer pharmagologic infusions are rarely if ever associated with an infusion reaction and can be given intravenously over 15-20 minutes.