Lots of stress and anxiety, missed period, abdominal cramping and gas. is this all anxiety and stress related?

No period: This may be stress related, your hormonal balance is may be closely related to stress. I however would make an appointment with your doctor, and take a home pregnancy test.

Who knows?: You know if you had unprotected sex. If so - pregnancy is a good alternative suspect. Cramps and gas can be from diet choices too. Consider a pregnancy test. Consider your eating habits. If you want a cleraer answer - see a doctor for an exam and tests as needed. Best!