Had my Period for almost a month (26days), had sex 2 days after period is gone. After 1 week of having the intercouse since period ended. I have started having brownish spottng for 4 days now. I am on implanon implant for 2 yrs?

Your hormones are in. .. flux for some reason, so hang on for the ride. Irregular periods and spotting could mean you may have some hormonal imbalance that could be affected by many different factors, not the least of which could be your implanon. They are supposed to last for 3 years continuously -- but sometimes that doesn't happen. Talk to your GYN about your irregularity and check a preg test while you are at it.