i didnt precum inside, or i possibly did?

I was recently "having some fun" with my girl and we played around and she stuck my thing inside for a while and we checked once in a while to empty out the pre-cum. it was the third time messing around that day so i came twice before this. And i also used the restroom before the third time. we keep on checking to see if precum comes out and nothing came out. but we ended up walking to a close place and bought a pack of condoms. now after a month her period is late. but she says her period is always late by like a week. but shes really scared now because we did it for the first time. shes becoming really stressed and lately she has been sleeping late. is that the reason why her period is late? she is losing her mind and is really scared.