I'm pretty worried

Ashlee • 20 years young (: ttc rainbow baby. baby dust and sticky baby's to all!
On Sunday I got my first faint lines, the next day I took a frer and got another faint line! I was so excited I told my BF but he didn't believe me, he wanted the line to be darker first and he didn't want to get his hopes up. so yesterday I took another frer and the line was still there, but just as faint, I was under the impression that they were supposed to darken. So I take a dollar tree test this morning (ran out of frer's and pay day isn't until Friday) and there's absolutely nothing. I mean, AF isn't due for another day, but if I've already had faint lines, they wouldn't just up and disappear of something wasn't wrong. Any input ladies?