results change over night!

So I posted my test results a couple of days ago at 14 dpo ( will attach pictures below) and it was a very very faint positive according to the ladies who have participated in the poll. now two days later that test appears to be a negative.

at 16 dpo I took another test and the line although still faint but showed up faster and i think it is a bit darker. maybe Im going crazy 🤔

My questions are;

1. is it normal for a test line to disappear over night? should i just disregard the change as it says on the box?

2. do you ladies think the line is getting darker ? had couple of chemical pregnancies before so dont want to get my hopes up.