Does this sound like PCOS?

1. My periods are irregular (I get them every 18-21 days) . Never have gone a full 28 days.

2. I grow a lot of hair under my chin and on my face that I have to constantly shave and when I shave it it'll be stubbly the next day. No one else in my family is hairy like I am. I also have hair starting to grow on my chest.

3. My periods are heavy and I can bleed through a super plus tampon in less than 2 hours

4. I am overweight and used to be 245 pounds when I was 16 (I am 21 and 217 pounds now) and it takes extreme effort to lose weight and keep it off. I gain weight very easily.

I've never gotten a scan to see if I have cystic ovaries and I'm not sure how to get diagnosed for PCOS or talk to my doctor about it, but I am 99% sure I have it. How do they diagnose it? Is just telling the doctor your symptoms enough or will they have to do blood tests and stuff?