Hi Doc i had a brief sexual encounter with a sex worker and during anal the condom broke , i noticed it after a few seconds , from that day which was 7 weeks ago , i keep thinking i have HIV , reason been i started feeling very tense in my back , followed by some muscle spasms or aches all over my body mainly my arms and back and then a stabbing pain in my armpits , i got a antibody test at 4 weeks which was negative , i think about it every single second , i read this could also be related to stress and anxiety please help