I started taking birth control again, and I always had an irregular period, but I have been getting my period like eveything two weeks and it will be like my period, but for 3 days long, and heavier. I have taken the same birth Control before, And it was nothing like this before. On top of that I sleep more frequently and I'm always having lower back pain. But I havent gained any weight, and the pregnancy test always say negative, please help