Pcos question!

Hi all, I was diagnosed with pcos in December at planned parenthood when I went in for extreme pain on my ovaries.. Turned out both of my ovaries look like "English muffins"they have so many cysts.. The doc said I would have a very hard time conceiving.. Well, luckily with no medication, I am 6w4d today! Yay! But! I am extremely nervous because she said I couldn't.. Could I miss carry because of the pcos or after you conceive you're mostly OK? I go in Thursday for first ultrasound but the obgyn told me two weeks ago not to get so excited.. I'm confused, im nervous and scared.. I just don't understand why I should not be excited. Any ideas on what she means?