Since I've Had The Implanon Inserted, I Have Been Getting

Since I've had the implanon inserted, I have been getting heart pulpitations, shakiness and have been diagnosed with anxiety. My doctor has me on half a tablet of paxtine a day but the pulpitations haven't gone away, I feel them several times a day.
I am not stressed/anxious and have been perfectly healthy until now.
I have smokes for years and drink a lot of soft drink/caffeine and it's only just happening since the implanon was inserted... Could this (implanon) be the cause?