Pregnancy tests that gets darker then lighter then darker again

I know so many of us are reaching for something when things don't look so good. I recently got a light postive pregnancy and 3 consecutive mornings first pee took more to see if it was getting darker or not. Has this happened to anyone and it was a positive outcome? Wondering if this is a chemical. I would be 4 weeks 2 days today so very early. I am turning 42 in March.

*update still not getting darker or lighter after waiting 2 days. Will wait another 2 day and test again. Doctor wont see me until 6 weeks so all I have is my pee and my sticks 🙈

** second update. Test line is now darker than control line at 5 weeks 1 day pregnant. Seems like it slowly rose. Doctor appt feb 19th. Just have to wait and 🙏🏼 now! Second pic dates are 28th, 29th then feb 4th. I ran out of the expensive pregnancy tests so now doing strips.

*** update feb 19th we saw a heartbeat! Everything looks good. Dated a little behind where I thought I was. I go back march 2nd to check again progress. 🤞🏼🙏🏼