In most cases Hepatitis B is a symptomless virus. First signs of infection could become visible after 6 months but it does not happen very often.
First symptoms of Hepatitis B are very similar to flu, you can experience tiredness, fever, muscle pain. You also can have nausea, vomiting, diarrhea, loss of appetite. Some people are ignoring these symptoms because they are thinking it's a normal cold or food poisoning. Very alarming symptom should be darker urine and yellow color of eyes and skin. Right now you could be almost sure that you will become infected by Hepatitis B. If virus will not become a chronic infection symptoms will go away after few weeks, even months.