First of all there was no need to have taken e-pills after the unprotected sex during periods.
Menstrual periods is the time which is supposed to be totally safe.
,loss of appetite,tiredness
are definitely the signs of side effects of e-pills but it is already a week since you took it and the effect should have wearied down by now.
Wait for another couple of days and if you don't find any improvement,then you should consult your doctor and look for other causes of nausea and loss of appetite.
or some viral infections like hepatitis can cause these symptoms to appear.