Have no clue how far I am !!

So I came off the Depo this year would say around march time .. periods started around a month after went to the Docters confirmed pregnancy .. I didn’t have a period in August so I would say from what I can remember I may have had one in July they were starting around the 8th or sometimes a little later .. have a scan on the 4th just wanted to know if anyone else has similar or anyone can work out how far .. only confused because periods came and went whenever