Control line getting darker 7 weeks 1 day, help :(

Hi ladies, I am currently seven weeks one day with my IVF rainbow baby. I have been getting really consistent dye stealers and I know I should probably stop testing. I decided to test today because I havent in about a week and my control line is significantly darker than the last time I took a FRER. I don’t have my first ultrasound until Tuesday and I’m totally convinced something is wrong. Has anyone had this happen? The test line looks really dark and is not changing so I’m hoping there’s nothing to worry about what are your

thoughts…