give me your opinion!

hi girls! i had sex on july 6th and i am on the pill. i messed up a few pills so i was nervous that i was going to get pregnant (should’ve used a condom i know). i got my period 5 days later and it was very normal. i also took a test today (18 days after sex) and it was negative. is it safe to say i’m not pregnant? just wondering because i’ve read that some women can still have their period if they get pregnant that close to having sex and then miss the next cycle. did i test too early? thank you for any responses!