I am on the pill, and usually have periods that are about 3 or 4 days long. This period, however, has been 8 days and I'm on the tail end of it now. Is this something I should be worried about? I have also been taking antibiotics for a throat infection.
It is possible the antibiotics have interfered with the absorption of the birth control pill hormone and that has changed your bleeding pattern. The likelihood of pregnancy is low if you have taken your pill daily, but it is possible for ovulation to occur on birth control pills, and fertilization to occur if you have otherwise unprotected intercourse, and due to the antibiotic, a change in the hormone levels may allow implantation and pregnancy.
If you are concerned, having a pregnancy test done makes sense.