Do a repeat scan to rule out ectopic pregnancy next week or if bleeding present. Take Progesterone tabs as support for early pregnancy both vaginal and oral tablets Yes u can take one HCG inj This is going to support your early gestation But review scans should help ! If u had irregular cycles then a chance of delayed conception is possible You should wait for two weeks Goodluck

Need to look at ultrasound report. Repeat ultrasound after week.