Confusing Test Results...Dont know what to think

Ive had several negatives up until this morning when i got a very faint line. So i used another more expensive test to double check and it was negative. The positive was on a really cheap ebay test that tests you five days before your missed period, and the negative was on a more expensive early first response test where you can test six days before your missed period. I would assume the early first response would have picked up any hormone if it was there, but its clearly negative. Now i dont know what to think.....what do yall think?