Does anyone have any experience with the first signal taking forever to turn positive and remain light?

I am sure I am pregnant. However it took a lot of time and money and prayer and fertility treatments to get pregnant with my son. We decided 2 months ago to start trying for baby #2. We wanted to try on our own for the next few months and start <a href="https://glowing.com/glow-fertility-program">fertility treatment</a> if necessary at the beginning of next year. Thankfully my body must have reset after having my son. I started getting sick after dinner every night around 8dpo. I took a first signal and it was negative. I continued to be nauseous for the next 5 days. I caved and took another first signal and it appeared negative. I went to work like normal and got home super late that night. I had thrown the test in a drawer. I opened that drawer after just telling my husband there was no way I wasn’t pregnant (I was super sick my first pregnancy the entire time, lost 20 pounds and threw up the entire 40 weeks, I was feeling the same). The test was OBVIOUSLY POSITIVE. I was worried because it was way past the time to read it so I took a clear blue that came with a OPK kit and it was also positive. I took it at 9pm. In the morning I took a FRER and it had the lightest line ever. If I hadn’t gotten two positives before I would have dismissed it as negative. I was worried that wasn’t turning and was talking to a friend about it. We had always heard pink dye were more accurate. She convinced me to take a digital at lunch and it came back pregnant. I have continued to take the first signal because I can’t get in for lab work until next week and they continue to be positive but aren’t getting much darker and still take quite a while to turn positive. I was getting worried so I took another digital yesterday and still positive. Has anyone had weird experiences with the first signal test not getting darker? I know I am over analyzing but I haven’t been sick in two days and my boobs are tender but not nearly as tender as I remember with my son.