Excited but have some questions FTM

I just found out I’m pregnant like 2 and a half hours ago😍🤯 and I’m wondering when I got pregnant... my doctor tested me on the 14th of August and it was negative. I’m pretty sure that shed be able to tell super quickly but idk.. does anyone have any idea how far along I am? I haven’t done anything yet because I’m still in shock and want to take more at home tests first... This is the first time I’ve been pregnant or at least I think it is so is there any tip/tricks I should know about??