What is going on???help

Hi I need some help, so I was on implanon bar(August 2015 - April 2016) and ever since I came of the bar I've had regular periods and then all of a sudden I got what I thought was a period 10 days before my period was due....doctor said it was breakthrough bleeding and not sure what the cause is (he said it wasn't from the bar) and anyway it only lasted about 3-4 days wasn't flowing was just sudden blood come out then stopped then few hours later a bit more would come out and I was thinking it could be implantation bleeding but not sure if implantation bleeding can be heavy, I have all pregnancy symptoms except for morning sickness, cramping and positive test as my period still isn't due until tomorrow and I tested 5 days before period was due NEGATIVE and tested the next day because im impatient and again NEGATIVE but my period is due tomorrow but I really want to be pregnant!!!Trying for 1st....has anyone ever had "breakthrough bleeding" and been pregnant still???? And also got cold/flu like symptoms which alot of women said they got around 4-5 weeks and if I am pregnant I calculated I would be 4 weeks by now....