Why are you bleeding 9 days before your actual period?

Ive been having unprotected sex.. my last period was may 23rd but i started bleeding April 15. But it only lastest for 2 days and it wasnt constant blood flow more like when i wiped or on my pantiliner it was brown and stretchy and red then pink then brown day before i started this i had unprotected sex and my boyfriend ejaculated in me he has before but tests results say negative and this started in Jan can i be pregnant this time?