Home pregnancy tests can be wrong, you are right.. Birth control can cause your periods to be lighter and shorter! Many women who are on birth control have a 2-3 day period, and that is all. Home pregnancy tests are normally accurate, it's just that some women test too soon. If you already missed a period, or your period was funny, and it still sayd neg, I would tent to believe it. You could always get a pregnancy test from planned parenthood.

Take at least one or two more preg. Tests before getting nervous. I look at bc this way: even with perfect use, it's about 97-99% effective, meaning that out of 100 women, one to three will get pregnant. I've know several women who have gotten preg. On bc when they didn't back it up with a condom, but most of the time, they skipped pills here and there or didn't take it within that 3 hour window or whatever. Just take another test, and if you're still skeptical, call your Dr.