hi i see that you had injection hcg and had cramps that is because of follicular tension and rupture. i normally give hormone support occasionally cramps can set in if periodes were to come. sometimes if implantation early pregnancy were happening occasionaly there will be increased blood supply pain similar to congestive pain. do not take pain killer.take plenty of waterand fruits .do not have undue exertion or intetcourse. wait for five more days .if periodes have not come go for beta hcg blood test in view of your pain. earlier test is not advised because of the interference ofthe earlier hcg injection with your test report. mean while when taking fertility treatment always retention cyst haemorrhagic cyst occasionally ectopic or mild torsion etc have to be thought and clinically and sonologically have to be corelayed hence follow up is very important.