Betsy you certainly didn't make him ill and it's great that as a new cat owner you're not scared to ask for advice. We all have differing opinions of wet/dry food but you personally wouldn't make your cat ill off them although he may have a slight intolerance to some things.
Wet or dry, premium brands are always better (Applaws/Bozita, follow the Zooplus link at the bottom of the page or Gourmet/Nature's Menu from supermarkets wet, Royal Canin, James Wellbeloved from pet shops dry). When I used to feed mine wet, however, they wouldn't go anywhere near Nature's menu or Gourmet but lapped up Wilko's own!
I think they do it to test us and even the most experienced cat owner will find their new cat has its own quirks.
Thanks for asking for advice, it's nice to know you care about your little one and don't be afraid to ask us anything, even if it seems obvious.