I am 21 years old and have had regular periods almost every time. My last period was Nov. 4-7. However, I missed both my periods on Dec 4 (due to a lot of stress around Final examinations time) as well as January 4th (due to starting to work out again and losing weight. My boyfriend came down from January 9-14th, where we had protected sex every day. We checked the condom and it did not break. Before this, I had not had sex since August of 2009. On January 14th and 15th I had some spotting. Now, today, January 22, I have had a bloody brown discharge. Why is this happening? COuld it be implantation bleeding? Could I be pregnant?