My periods are irregular, I had sex on the 13th, 19th and 28th of December, I thought I was getting pregnancy symptoms such as backache, lower stomsch cramps, lightheaded, dizzy, tired, breasts pain, I took a test which was negative however was going to do another in a week or so, today I woke up and was bleeding like a period but the blood was light red, I checked when I would ovulate and it told me the 28th December and I had sex on that day, could someone please help?