Could Implant Cause Erratic Bleeding?

Hi, i am 23 yrs old and my history with contraception is as follows;-

Contraceptive pill for around 3 years then changed to the mini pill due to high blood pressure. I stopped taking the pill approx 2 years ago and have had the implant in for a year. I have had intercourse three times this week and each time about an hour or so after i get bleeding which lasts for about a day after and then stops, this is the second time this has happened to me as i had it about 3 years ago also....a little worried, can you help??