is my doctor right about pcos without doing any tests?

Hello, my doctor diagnosed me with pcos shortly after she diagnosed my sister with it( we have the same primary care) my sisters symptoms were, excessive hair and weight problems. I on the other hand am skinny with thin hair. I have been on birth control since I was 14 and had a regular period every month. 2 years ago I decided I wanted to get the Mirena, once I did and stopped my bc pills I got bad acne which I've never had ever before, and my hair has gotten very thin. And because of the Mirena I haven't gotten a period. Me and my so decided we were ready for a child so I got my Mirena out a month ago, I got my period shortly after I got it out. I'm worried about chances of not being able to get pregnant. I don't even know if I truly have pcos or how bad it is my doctor just told me I had it without any tests.