Late AF ?

I am so annoyed. Done 3 tests over the last 12 days and all bfn. Anyone experienced a late bfp or an I just trying to kid myself?
 One of my closest friends rang today to say she is expecting baby number 4, she had been dreading telling me. I am happy for her but extremely peed off with myself that I haven't got anything yet. 
Anyone been in a similar situation and AF showed? Or got a bfp? My mind is kinda working overtime and over analysing every possible symptom or slight pain etc. as hard as I try not too ?
Sorry to ramble!!