Any idea?

Hey guys so I really need to stop worrying but me and my boyfriend had sex mid July with only a condom and he didn’t even finish, I then started a I think a light period in the beginning of August for about 5 days, and then I started another super light period a few days ago, I am super stressed and scared I’m pregnant so I took a digital clear blue pregnancy test and it came up negative, its been about 7 weeks since then so, do you think it’s accurate? Keep in mind my periods normally were in the heavier side but lately they’ve been wack (light, and starting and stoping) I’m praying I’m not pregnant, please help 🙏🏼🙏🏼