Hello and Welcome
I appreciate your concern
Secondary amenorrhea can be due to a number of reasons. its good that you tested for pregnancy , first. If the test was negative and confirmed by blood hcg levels or Obstetric U/S then you can Norethisterone and Ethinyloestradiol combo meds like Penorit can be taken to induce period, in consult with your doctor. Infertility workup looking for anovulation, PCOS, fibroids , ovarian , pituitary dysfunction should be done. Clomiphene and GNRH analogues are possible treatment choices if you fit the criteria e.g anovulation and there is no other cause e.g PID or low count / dysfunctional sperms.
wishing you best of health
thanks