According to the history you have given, if you are having regular cycles, you had intercourse during the fertile period of your cycle, so chances of getting pregnant are more. Nipple discharge
occurs during early pregnancy
so also increased vaginal discharge
and nausea. I suggest you to see a gynecologist for an examination and you can also take a HPT. In case your pregnancy is confirmed, you should quit smoking
as this is going to harm the baby. Take care.