16dpo faint lime I’m worried that it won’t stick! Help

I really thought I was out this month because when I took a test on the day of my missed period it was stark white. I am 2 days late and I had one more test so I just thought use it up so you don’t have any more in the house. I drink only water during the day and tested after I got home at 3:30 and this showed up!! BFP I am extremely shocked and so confused and nervous!! I’m feel so blessed but would love to hear your stories of late BFP and everything working out just fine!! Baby dust