Can I be pregnant on implanon

Its always possible... no form of birth control is 100% effective. Thats true whatever your weight.

I'm on the implanon and it expires in June, I've been having unprotected sex and in February I started to spot it has never happened since being on the implanon and now in march I had white discharge, I been very irritable and moody and most of all tired can I be pregnant?p.s and I'm overweight and heard the implanon is less effective when you are...

No form of birth control is 100 percent. It is completely possible.

From Implanon's site (Official website for IMPLANON® (etonogestrel implant) 68 mg (http://www.implanon-usa.com/en/consumer/index.xhtml)):

If you become pregnant while using IMPLANON, you have a slightly higher chance that the pregnancy will be ectopic (occurring outside the womb) than do women who do not use birth control. Ectopic pregnancies can cause serious internal bleeding, infertility, and even death. Call your health care provider right way if you think you are pregnant or have unexplained lower stomach (abdominal) pain.

Because of the possible side-effect of an ectopic pregnancy, you need to contact your doctor.

If you have been worried about becoming pregnant, you may be more sensitive to normal hormonal fluctuations and changes in your body. However, better to err on the side of caution.