MMR Shot

So I just got my blood drawn and some type of shot to boost hormones and have to go back tomorrow for more blood test. I have a sonogram scheduled for December 1. Since it's over a month away, I decided to get my MMR shot (I don't know why I never got it and was able to go to school). Couple of questions...How long do I need to wait til we try? One said a month and another said three. And do I need a second shot in a month? I read that I did online but a nurse said "it depends"