Hi,Dear.Welcome to HEALTHCARE MAGIC.
If you have just started taking the pills then for the first 7 days of taking the Pill,one should use an additional form of contraception
, such as condoms, to prevent pregnancy
After 7 days of taking the pill regularly you don't need any other method of contraception.
As from your question i am not able to appreciate the exact number of days after which you had unprotected sex.So i am not able to tell you that there are chances of getting pregnant or not.
And the nausea
and sickness may be due to the pills because you will be having these symptoms due to taking the pills initially.
If you do not get your periods on time then go for a pregnancy test after 7 days of missing your periods because before this the test is not much confirmative.
Hope fully you will be getting your periods within 28 days of starting the pill.
Hope this answers your query. If you have additional questions or follow up queries then please do not hesitate in writing to us. I will be happy to answer your queries.
Wishing you good health.