Why is it low? Before you can fix it, you need to diagnose it. Either your testicles aren't working or your brain is not asking your testicles to work. There is medication for all of that. Time to call your family doctor. If you family doctor does not know how to help you, then ask for the name of another doctor that can help you.
Several situations! First, women with polycystic ovarian syndrome can have both an elevated total and free testosterone. Passive contact with a male using transdermal testosterone can do this. And finally, some women will have levels that are high for no known causes!