My first BFP. Can someone help with the math 🤣

Fi

So i tested yesterday on clearblue advanced digital and got a bfp and it said 1-2 weeks. Below is my calendar from glow. I can't quite do the math, my ovulation date kept shifting as i kept getting negative opks. Originally it was around 14th i think. I have tried to calculate my due date but pretty sure i am doing something wrong. I had very light to nil spotting from 28th March for 3 days. So i tried putting my last period date as the one in feb but that would mean i am 5-6 weeks surely? When i put 28th March it says 1 week pregnant so i am guessing that is right? Can anyone help? So useless and new to all this 🤣