Thank you for your query.
Firstly , the symptoms that you describe could be caused by hormonal disturbances.
they could be because of the Implanon itself.
Rarely, even with an Implanon, pregnancy
Even an ectopic pregnancy is possible.
Other causes include hepatic damage, renal alterations, diabetes, hypotension
, thyroid or other endocrine disturbances etc.
and waking up in the middle of the night could point to a cardiac etiology.
A gastrointestinal infection
also could present with such a picture.
Please understand that you need to have a complete check up by your physician .