Weeks of pregnancy

First day period: july 11,2023 Last day period: july 15, 2023 Dumating si hubby from ibang bansa is july 21 so yun ang unang sexual intercourse namen after that almost everyday na hanggang hindi na ako dinatnan ulet and then pag check ko buntis nga ako then nangpunta kame sa ob just to chech kung ilang weeks na pag sabi ng ob is 6w2d suddenly ng doubt sya na baka hindi saknya yung baby dahil aug 22 nung nagpacheckup ako sabi nya is diba dapat 4weeks pa lang if ever na buntis ka pero baket 6weeks? Can you pls elighten me po paano ba ang count?#pleasehelp #advicepls