IB or not IB that is the question.

Hi Lovely Ladies,

So this month I though the painful wait for the bfp or bfn would not be an issued, my husband is away for work and left on the morning of the 15th. My O day was due on the 20th and of course my dh is away until the 25th. No hope or so I though, 

This morning I woke up to a light brown discharge, its there when I wipe but it never gets to my clothes but its a week and three days ish, I am never regular, until my af.

Now of course I am praying this is IB and getting my hopes up... again, although I am desperately trying to reason with myself and say it cannot be, it would have been 6 day old sperm by then, it seems so unlikely we would have been struggling when ttc if the little swimmers were that super, surely. 

Has anyone else conceived with sperm this old, has anyone else had something like this and then not been pregnant?

I am probably not, surely not pregnant but I really wish my body would not do these weird things just to get my hopes up before they are cruelly dashed again,.