How many NEG's did you get b4 the big BFP?

Ok I have been TTC and I'm due for my period on the 18th or 19th of this month. I tested this morning and it came up negative. I was a little bumbed out but I know that it can come up NEG sometimes and still be positive later on in the week. How many NEG's did you get before you came up BFP....and when did you take those tests?