quick question

I'm nearly 23 years old and 3 years ago my dr told me it would probably be hard for me to conceive but for the last year me and my partner have been trying for baby #1

My periods have always been regular (come on the day I'm due at 11am every month) but January I was 3 days early and February I was 8 days late while experiencing pregnancy symptoms. I started bleeding but it didn't feel like a normal period, it was a really light flow but was thick and a dark brown colour and then for the last half an hour it was like fresh blood. I took a hpt on Monday just to be on the safe side and it came back negative. Since yesterday I've been having flu like symptoms (headaches, sore throat, hot and cold sweats, aching all over but mainly my lower back) I've lost my appetite and normally I can eat for England. Could this be anything or is it something I need to be worried about?