Line on opk while on birth control??

I’m on birth control pills and have been for months. I take it exactly as directed. This past weekend my boobs were sore and I’ve been crampy. Last night was so bad with cramps. Nothing since with cramps. But my boobs haven’t hurt since Sunday which was bad. I’ve had a lot of clear and egg white mucus since Thursday. I’m not pregnant but I had these that are still in date from when we were trying for our second baby. I just by accident found them in our medicine closet cleaning and wondered hmm and took one just now with a one hour hold middle of afternoon. And this showed. It’s not ovulation but why would I even have a line and not a faint one?? Being on birth control. I’ve taken opks before when trying for a baby and I have had them look like this and grow darker and then after I ovulated there was no line anymore. And it was a steep decline in color rapidly. Within a few hours looked like this then nothing. When I’ve ovulated before I’ve had cramps and discharge and achy boobs for a few days. Lots of discharge. I truly just found these and wondered because I’ve had similar symptoms and it’s been ovulation in the past. I thought birth control prevented you from ovulating?? This looks like I’m gearing up to ovulate or just literally ovulated. Is this normal? Has this happened to anyone else? And how?

Also to note I have never had a period on birth control. In almost six months I haven’t. I had my first period after having my baby super early on before starting birth control and not a single drop of blood ever since.

Edit: yes I know it’s negative. I’m not saying it’s equal color or a peak and surge. But mine have never had this much color except ahead of ovulation coming or immediately after then it drastically decreases and is hardly noticeable. Look at the attached photo that shows the color isn’t always there.