Period only lasted 3 days, could I still be pregnant?

[NinaK32]

OK so usually my period last roughly 7 days but this month it only lasted 3, for the past few weeks I thought I might have been pregnant, I had symptoms like sore breasts and sickly feelings. Thing is a few days ago I started my period a day early but also became extremely ill the same day, serious back pains severe headaches, stuffy nose, sore throat even losing my voice. My period has also been rather weird, apart from only last 3 days it seems to have been really light and mostly consists of clots and very little is actually on the pad and what is there is like a dark brown in colour. Could I still be pregnant? Or could I be seeing a result of miscarriage?