+opk?

Can I have opinions on this opk please? I took one with FMU (I know you're not meant to but work makes it difficult for me to test) and got a very definite positive. Managed to take another (of another brand) at lunchtime and got a negative but just took this one now (same brand as this morning) and I think it looks positive again? What's going on? I always find with these tests one part of the line looks darker and then it fades. Anyone else get that? X