I don't know for sure how far along I am.

So J just found out last Friday that I am pregnant. Last menstrual period started June 21 and that makes me like 7 weeks and few days pregnant. However, I have tested allthrought July and got all negatives. On the other hand, I ovulated and BD on July 30 which makes last Friday my 10 DPO. My period has been so irregular that I am not for sure how my body is working right now. What do you think? Also, is there any test OBs are doing to determine how far along you are aside from the 12 weeks ultrasound that you know of? What's your take on when my due date is? Appreciate your input! :)