Implantation bleeding? please read and help!?

ok so i discovered that i only have about a 7-9 day LP by taking opk's. so when i tested pos i BD. on the day my period was supposed to start it was just two light spots. for the next 4 days it was very very light and light pink/brown. i tested all the way up till AF started and got BFN but then two days after i finished i had a wierd feeling to test (which ive never had before) due to symptoms. anyway, it was a BFP on an FRER. it came up instantly but it was light.. which could be due to the fact that i had to squeeze out that pee to take it lol. anyway, is it possible that it was IB? anyone have IB and what was it like? ive also had a couple of times where i had brown CM ... sorry for TMI but ive had 1 healthy pregnancy, 2 MC, and 1 chemical. this hasnt happened with any of them! im just in a state of shock/panic right now and dont know what to think. please give me some honest answers. also i have no cramps but i do have a few minor pregnancy symptoms but nothing major yet.