faint line on first response 4days before period due.
I think thats a positive hun, but I'm not 100% sure as first response do come up with some pretty bad indent lines fairly often. I'd test again in 2 days if it is a positive it should show darker by then
It looks like an early BFP, but as misskiwi said first response are know for bad indent lines. Good luck for your retest hoping that is a BFP for you xx