Please no judging

So I'm due October 20th however I swear my last period was January 8th, which would make my due date October 15th...however the doctor office is saying my LMP is 1/13/18 making me due October 20th....on the week leading up to the 27th I had unprotected sex a lot back to back where he finished in me, but on my estimated "conception date" based on online calculators which to my understanding base your ovulation off 28 day cycle which I don't believe mine are it says estimated conception date 1/27/18 which is a day we had sex but he pulled out jacked off then came in his hand, why idk lol...BUT my cycle is usually same day each month or maybe 2-3 days after same day each month no later. I'm all sorts of confused 🤷🏻‍♀️ and still pregnant