I have used pregnosis clear in stream and had at least 4 false positives all in the time frame and were very visable lines. I had a blood test done the next day and definatley not pregnant hcg under 2. I have heard alot of bad report of pregnosis but not on first response so maybe if it is showing up on another test I would think you might be but you do really need a blood test expecially over 7 days the line should get darker.
Good luck I hope it is a BFP!