I had unprotected sex about a week and a half ago (Jan 11 or 12) I was barely off my period,a few days later i had sex again this time using protection but the following morning (Jan 18) I noticed a spot of blood in my white shorts. This blood was dark red and only happened once that day. The next day it was back but more of a brownish color. It skipped the 20th but happened again the 21st. My periods have always been very regular and predictable and not to mention I got off less than two weeks ago. I think what I may be experiencing is implantation bleeding. I have no other symptoms of pregnancy. Could I be pregnant?