FIRST RESPONSE??

Has anyone ever had any trouble with FIRST RESPONSE PREGNANCY TESTS? Have they ever failed you? Indent lines? I had a white very skinny line on one of my tests yesterday and it had no colour to it. 
I Have used like 8 first response pregnancy tests, they have all been negative and Have had 2 periods since I last had sex. Is it safe to say I'm not pregnant? Would at least one of these test come up positive if I was pregnant? I'm just a worry wort. I'm on the pill and my boyfriend used a condoms!