Last month I brought a box of frer. I used two of the tests and they both came up with extremely faint second lines but then af showed up. So I assumed it may of been chemical pregnancy. Now this month my boobs have increased in size and feel swollen and sore. So I took a test from the same box as last month and that gave a clearer second line but still faint. That night I went up the shop and brought a new three pack of frer. Did a test this morning with fmu and its a bfn. Not even a chance of a second line. Is it possible that last months box was a dud batch?