Welcome to HCM,
after going through your history, you had unprotected sex 2-3 times during fertile period, sex 1 day before expected period chances of pregnancy
are almost nil but you did have sex before also even if ejeculattion is not there are sperm present in pre cum.
So it is possible to become pregnant and if your period is delayed then you should do a Urine pregnancy test further action depends on result of test.
is hormone tablet used for secondary amenorrhoea under supervision of Gynecologist that is why you must consult Gynecologist as soon as possible as this tablet some time can cause bleeding PV.It is better to consult expert Gynecologist.
There are many safe option are there which your Gynecologist suggest and suitable can be used for your case.
Hope everything improves this time,then please remember to practice safe sex
as methods like condoms not only protects from unwanted pregnancy, but also protects from sexually transmitted diseases.
Please take care
Best of Luck.