I have a very regular period that lasts about 4 days every month in the beginning of each month. I had sex on one of my ovulation days... and now I have 2 and half weeks until my next menstral cycle, I started spotting ligth pink and clear blood type fluid. Can I be pregnant? I have been getting headaches and I never got headaches ever. I also get nausea randomly but never throw up. I also get achey in my lower back. I took a clear blue pregnancy test and it came up negative... could it be that I am pregnant or is it something else?