If it’s the first time you’ve had irregular cycles I suggest you do a blood test to rule out pregnancy first(bHCG). If negative you can take withdrawal tablets

There are various reasons of irregularities of mensis. Are you married? Or sexually active?? If so do a s.bhcg rule out pregnancy.  Do have pelvic sonography if it happens again. Go for withdrawals of periods. Take tablet meperate 10mg twice a day for 5days and then u will have periods in a week of stopping the medicine.  So s.tsh too if u go for s.bhcg.  consult me in private chat if u want to discuss all your reports.

May be harmonal imbalance get a us pelvis scan and thyroid test with haemoglobin