pregnant symptoms??!

ok so i had sex two weeks ago with my ex boyfriend and we didnt use protection although he pulled out but not quite on time!!! lately i havent been able to eat certain foods and sometimes the foods i eat would taste so weird! ive been feeling nauseous and having back pain. Never thought about be pregnant bc i wasnt getting any symptoms since last week on friday, so i drank and got drunk but this was all before i started feeling sick! should i still be worried and take a pregnancy? pls give me feedback!