What do I think abt this pregnancy im kinda anxious

So I had sex around the start of augedt and had spotting for 2 weeks till the beginning of September a week after I had sex (so around augest 16) and I was getting on and off positive tests around the end of augest. And most of them showed positive after 20 minutes then so I was confused.I was just gonna wait till my next period to freak out, it is now the beginning of October and I didn’t get my September period. (I also had sex with a new partner after the partner in augest) I’ve been taking pregnancy tests and they all turn positive quickly. I went to the clinic today and it was positive there too and we did an ultra sound but they said it was too early to tell how far along I was. They were able to see the endometrium sac thickening though. What do u think and what do you guys think abt this? Also who do you think got me pregnant. The partner in augest or my partner in September? Im just confused how far along pregnant I am especially if I thought I was in augest, wouldn’t I be able to see by now unless my most recent partner got me pregnant. PLEASE ANY OPINIONS WILL HELP!!