As of today my period is 8 days late and i have taken 4 home tests (1 this morning) and all have been negative. could i still be pregnant?

Not if negative : Home pregnancy tests are very accurate. They are the same tests used in a doctors office. They can detect a pregnancy 7-10 days after conception. If you doubt the result you can repeat it in 1-2 days. If you were pregnant the hormone level would rise enough for detection. After this much time clearly you are not pregnant. See your doctor for irregular periods.