Talk to Gynecologist on Pregnancy Issue

My fiancé is 3-4 weeks pregnant and it was all unexpected i havent checked it if she is really pregnant or it is just hormonal imbalance because in her last periods she was going through hormonal imbalance and taking med called ferosoft 100mg and she took is for around 20 days last month. We had sex but i never ejaculated inside but yes intercourse did happened. Her last periods date was 27th of may and we had sex at 14 june and then she has missed her periods. She is 19 and now we are really worried and dont really know what it is. She had the back pain that she always get before her periods but she didnt had periods this time. Other than that yes her mom also go through problems of hormonal imbalance but i am just confused what it is. If she really is pregnant how can we abort it at home.