Line progression stalling? FRER 15 DPO

I’ve had a previous loss and this is my first pregnancy after that so to say I’m a bunch of nerves is an understatement. I’ve been testing everyday even though I know HCG doubles every 48 hrs, I just can’t help it. But I’m very concerned because I’m now 15dpo and I feel like my frer’s are starting to stall. My husband can swear he sees the tests darkening a bit but I’m having a hard time seeing it for the past few days and feel like it should be much more significant than it is. It also doesn’t help that with my loss, I started to have a dye stealer already at 14dpo. The earliest appt I could get with my OB isn’t for another week. Is this line progression okay or should I continue to be super guarded?