Hi You All I Have A Random Question And I

Hi you all i have a random question and I hope i can find the answer on here who has had some what of a similar experience, i had unprotected sex with my GF while she was on her last days of period and she is also on Birth Control (Implant) i ejaculated inside of her and she has been having a lot of symptoms like craving certain food constipation and sore boobs for a while now , she got tested in a clinic (Urine Test ) and the pregnancy test was negative, what are her chances of being pregnant at this situation? She is going to get a blood test but i am just worried about the whole situation and i am wondering if its a good idea to still keep the implant in her arm coz it could hurt her and the baby if she is , any advice will be appreciated.