Even a small dip can effect your libido! I had test after test run for years and was told over and over again that is wasn't enough to make a difference. A yr ago I changed to birth control that has no estrogen at all, and suddenly, I'm back to normal. I want sex, I'm off my psych meds, migraines are undercontrol. It's been kind of amazing.
So I went back through all my old blood tests and sure enough my estrogen was on the high side of normal and test. on the low side of normal.
The thing is we all different on what 'normal' is. Just as we women differ from how much is 'normal' for us vs you men. Every individual is different as well. That small dip may actualy be enough to make a huge difference. Advocate for yourself. If you really feel it is the hormones, find a dr that will listen. It took me 6 yrs and threatening a lawsuit to get answers, but I got them and as much as it sucked to go that long, I now have the ability to live a fulfiiled sex life.
And BTW it never bothered me either. Karma used to say I was the only woma alive who would rather clean a house than have sex. But I just didn't care. I didn't feel like I was missing anything, because I was so used to not having it.