Its really really common to miscarry with no symptoms?

So far my pregnancy has been smooth sailing, I'm 9 weeks along taking prenatals, folic acid vitamin E and metformin (I have PCOS) I've had an ultra sound and the heart beat is great and my HCG leves are super high and my doctor says that's great. My odds of miscarrying at this point should be around 0 but out of curiosity I texted KGB and asked if you can miscarry with no symptoms and they said its VERY VERY common to miscarry without bleeding or cramps or pain at all- which got me very upset because my pregnancy symptoms are calming down, I'm not as naseous any more and I don't have to pee any more than usual, also I'm having little to no mood swings and my breasts aren't the slightest bit tender. So I'm worried :(