10miu one step pregnancy tests

I have took 2 of these tests
1 has a vvvvvvvvvvvvvvfl on it and the other you can sort of see something
However on both of them when you shine a light to the back of them you can see a most certainly a PINK faint line!!!!
On all the other ones I have taken (the same tests) they don't have any form of line when shining the light behind
Please please someone respond and help me!!! 😔😔
I also have backache and lower abdo feels sore and hard as if I'm constipated but I'm not! 
Had headaches for 4 days!
I'm due period in about 4 or 5 days
Help