thanks for your query.
The symptoms that you mention, such as nausea, smell perception, sore breasts etc, are common the birth control, but should not occur towards the fag end of 3 years.
and frequent urination
are not normal on Implanon.
please consult your primary care
physician for the cause of these cluster of symptoms.
With two negative pregnancy
tests, you are least likely to be pregnant, but your check up will clarify that also.