Thanks for the query.
Missed periods could be due to stress, hormonal
imbalance, Excess weight gain/ loss, ovarian cyst
I recommend you to get relevant tests like thyroid profile, Ultrasound
abdomen and pelvis.
Treatment depend on the diagnosis.
Since yo are having painful cramps, you are likely to get back your periods in a day or two.
If you do not get your periods in another 1 week, i suggest you to consult your Gynecologist.
Hope this helps.