First response tests - the control line

I’m about 7w now and I’ve taken a few tests to ease my mind at times and the control line has fluctuated in darkness from being very light (test like is very dark) to medium. Every time, the test line has been dark regardless. Should I be worrying about the variance in darkness of the control line? It just worries me. I have my first us this afternoon so I guess I’ll know more soon but oh my god this is a wild ride of anxiety and nerves in top of feeling sick every day.