Naomi,
Do you mean you did another Discover HPT and there is no second line.
Or, do you mean that there is no second line on the opk?
Or, do you mean the line on the hpt from yesterday has disappeared?
If you mean the latter I urge you to contact the company - the phone number is on the box. Demand a full refund and they will oblige. This is becoming a joke with the number of false positives with this brand...
Hugs