Baby Shower Frustration!!

I had all of these people who wanted to go to my baby shower, and here we are 2 and a half weeks from the shower and I have only received 8 RSVP's. I don't know if people plan to just show up and not tell me prior to the day or what. It's starting to make me angry. I had to go print all of these extra invitations for my SO's work friends and only one of them RSVP'd. 
This is frustrating me more than it should, but how are we supposed to know how much food and things to get if I don't know who is coming?!!