Hello,
Welcome to ehealthforum
It was a good idea to start the pills as lack of periods can even cause fertility issues.It is quite common to have symptoms as nausea,cramps,abdominal pain,bloating,headache,fatigue while on the pills.These are usually present for initial few months and then subside gradually.
Also I would like to advise you to get USG scan done for pelvis to rule out ovarian cause as presence of cysts.
Take care!