dont know if hes my babys dad or the second guy ...

so im currently pregnant due june 9th but im very confused i might sound stupid but i really want to know

i had PROTECTED sex with an ex a day before my period had started

which my last period was september 3rd it lasted 6 days so i ended it on the 8th

on the 10th of september i had got back with my other ex boyfriend and we had
unprotected sex


the guy i had protected sex with said the condom didnt bust and i believe him cause i know he would be freaking out and what not (he didnt know i was pregnat)and i member i saw him checking it after we had sex

but in a way im scared cause i dont know if hes my babys dad or the second guy
because the weeks dont add up to me i try counting from the 10th of september and im always a week less but when i count from when i started my period it adds up right
when i use a concieve caculater it says i concieved the 17 of september
when i looked into it, it says that doctors count from when your last period was before you got pregnant



can someone explain im so confused i hoped all this made sence lol