Hello,
Welcome to ehealthforum and thanks for writing
After the sexual contact you had normal periods and also immediately started the pills and if you have been taking the pills regularly withpout missing any dose then possibility of pregnancy is almost nil.
The various symptoms as irregular periods,mood swings, bloating, nausea, headaches, fatigue are due to the oral contraceptive use and are very common effects present for initial few months until the body gets adjusted to the hormonal changes.It seems you are also experiencing them because of the pill use.
COnsider taking the pills regularly every day and avoid stress as it can cause further changes in the cycle.If you notice any unusual symptom as missed period for more than a month,cramping associated with severe prolonged bleeding etc then consider visiting a Gynaecologist for evaluation.
Take care!