Pregnancy tests

Dayle

So I’ve completely missed my period (8days late) and I’ve taken a few pregnancy tests, 2 were negative and 2 were positive but the way it worked out was like

1st one: negative

2nd: faint line

3rd : positive

4th: negative

??? Waiting a week before I retest but just wondered what people thought could’ve caused this, will be making a doctors appointment on Monday!