Could i be pregnant? how long does it take a sonogram to show that ur prego?

I think I may have gotten prego last Thursday so a little over a week ago. I had to have a sonogram done on Tuesday because I've been having really bad cramping for about 3 months now. They didn't tell me I was pregnant but that I have to have a surgical procedure done so they can go in with a telescope and look closer at my organs. I'm afraid that if I'm prego that this will hurt the pregnancy. How long does it take for a sonogram to be able to show that u are prego? And what should I do since they want me to have this procedure done?