Should I be concerned?

LittleLuvBug

Took another test today (kind I've never used, w/ a dropper) & while it read BFP, the line took a while & was fainter than I'd like. When I took my 1st test about a week ago it was very fast & strong. Is this just a testing method difference, or should I be on the lookout for mc?? If it matters, the first test was one of those early response tests & this one was a cheapo from the $ store. I've had 2 chemical pregnancies in the past & am terrified I'm going to break the big news only to lose the baby :-(