Line not showing anymore?

So I got my first BFP at 10dpo and it was very noticeable! I kept getting the line and it wasn’t much stronger but I did get one yesterday as well on a first response. I just took a cheapie Amazon one this morning at (4 weeks and 2 days) and it’s not dark anymore, it’s not as dark as it was the first time. It’s almost not noticeable!

Has this happened to anyone???