18dpo 6days late 4bfn's

This month was the first month using preseed so I had I high hopes. And to my surprise, my AF was late!
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​    I was so excited because since being on bc for almost a year now my periods have always been on time. So when AF didn't come on the 14th I was so excited. 
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​  I tested that day and got a bfn. Which I figured wasn't uncommon so I didn't worry. Over then next couple days I had cramping. I've been super gassy, sleepy, moody etc. 
​Well now it's 18dpo, my AF is six days late, and I took a mother test this morning as soon as I woke up and still a solid bfn. 
​I just so tired of hoping and being disappointment. Has this happened to anyone else? Should I give up hope now?