Question!!

So 9:40pm at 8dpo i had a noticeable faint line and could be seen by othets too. Tested again next morning and it wasnt there. So i keep testing every couple of days. All i get is vvvvvvvvvvfls that im like is it there or not. Tested again the other night and got another noticeable faint line then next morning it wasn't there. Im now 6 days late. Anyone know what could be going on?? Any any ideas?? Did i just get some bad tests??