K what the hell

Yesterday morning I took a wondfo hcg and it showed a very very faint positive. Than yesterday evening at around 7 I took another one that was still light but much darker than in the morning. I took another of the same brand and there was barley a line , so
I took a first response and there's a clear darker line. I'm so confused. Why would the wondfo show negative with fmu when yesterday's were positive without even using fmu?!?
 Bottom cheapie is from this morning, other 2 are from yesterday.