What Are The Side Effects Of Implanon Contraceptive Implant?

I have been on the implanon contraceptive implant for the last 5 years, 3 years with first and now into year two with the second, I have always been fine with it other than slightly prolonged periods however last month I had a period for 6 weeks (only just finished) which was more like mid than menstrual bleeding and have had pregnancy symptoms for the whole 6 weeks such as nausea, not being able to drink tea as with my other pregnancies, feeling faint, sore breasts etc. I'm really worried as I can't imagine these side affects
Would only just be kicking in after 5 years. Do you have any advice please?