I am a 21 year old woman and are wondering if i might be pregnant I had my period last week Friday and had it just for a day and after that day I started having small amount off bleeding. Could i be pregnant. I also have constant headaches and my lower back hurts I checked my weight on Monday and I weighed 50 kg two days after i weighed myself I weighed again and saw that I lost 2 kg is. I did a pregnancy test on Tuesday and it was negative can I still be pregnant???