3 diff FRERs taken showed lines way past the time window...are they valid?

Ok so 11,12,and 13dpo i took FRERs and didnt see a line at first so i threw them in the trash. Later i got them out just out of curiosity and all 3 had very faint lines!!!! Does this mean they were positive or invalid bc they showed up after 10 min? And is it just a coincidence that all 3 showed positive lines but very faint? Im just wondering if i shld get excited or not yet....any advice would be appreciated!