Being pregnant is so freaking confusing😜😩

I went to my first Ob visit my LMP was September 7. So I used the little pregnancy calculator and it stated that I had a June 13, 2020 due date. The receptionist said my first appt. had to be after the 19th. I go to the appt and the doctor looks at my teeny sac and states that I'm pregnant. She makes a confused face then looks at my chart and then says oh yeah you have pcos so for you the date would be different.

Of course, I'm thinking geez broken vagina strikes again. So they aren't sure what my due date will be. The OB thinks I MIGHT be 4 weeks along. Unfortunately they can't see a heartbeat until 6 weeks. Even though it is 6 weeks, which in my world 6=4. Seeing as though I have a Ph.D in Google. I requested that my hormone levels get checked since PCOS might be striking again. The Dr. mentioned the other possibility is that it could be an abnormal pregnancy. She was super knowledgeable and friendly when she came in, but when she was leaving she was unable to hide that she was perplexed.

So, I got shipped off to get blood drawn. I get sucked in to a convo about plaster walls and 3m tape(don't ask). I'm told to come back in 2 days and get more blood taken , which is fine. Then I get ready to leave and I'm told to schedule another appointment for the ultrasound for next Monday.

Next Monday won't I be 7 (I mean 5 weeks pregnant) at which point they won't be able to see anything again?