Girlfriend period was supposed to come on the 12th now its the 15th and hasnt arrived. she has been feeling more tired than usual for the past week and had constipation & diarrhoea for the past few days. is she pregnant? we only didnt have sex?

Home pregnancy tests are very good at determining pregnancy. They can be positive as early as the first day of a missed period. Feeling tired, constipation, diarrhea are not specific symptoms for pregnancy. Pregnancy symptoms to look for: Breast tenderness, mood swings, nausea/vomiting. Periods can be late for a variety of reasons including stress, weight gain/loss, new exercise regimen, etc.

If your girlfriend, not you, your girlfriend, did not have sex, she is not pregnant. If her symptoms persist or get worse, it would be prudent to see a doctor.