I've had unprotected intercourse a lot in the past 3 months.. Not sure exact days but they were close together. During those 3 months I did not have a period. Instead on July 19th, I had a darker brown discharge that was light(not heavy) and lasted only about 3 or 4 days.. On September 1st I had intercourse again and that was the last time.. September 3rd and 4th, I had very light pink discharge that only was seen when I wiped.. Today, September 5th I got some more blood that is light enough to use a panty liner with.. Nothing heavy. I have been urinating a lot more, my smell senses are sensitive to a lot of things, slight cramping, lower back ache, breast changes, etc have all been occurring as well, and I'm just curious to know if I'm pregnant and this is implantation bleeding, or if something else is wrong with my body? (I've never had a late period!)